Bans on highly toxic pesticides could be an effective way to save lives from suicide
Pesticide poisoning is a common method of suicide in many low- to middle-income countries. Banning highly toxic pesticides and substituting them with less fatal ones can save lives.
Note on content
This article contains an in-depth discussion of suicide deaths, including motivations and methods, which may not be suitable or helpful for people who are struggling with serious mental health issues.
If you are dealing with suicidal thoughts, you can receive immediate help by visiting resources such as findahelpline.com.
Preventing suicides can seem like a much more difficult problem than many of those we cover on Our World in Data. The number of people dying from suicide each year has barely changed in decades.1 Mental health problems, a key risk factor for suicide, are complex and don’t have a single or simple fix. You’d be forgiven for thinking that reducing suicide deaths would be slow, if it were possible at all.
Pesticides are used in 14% to 20% of suicide deaths globally — 100,000 to 150,000 deaths each year
However, many countries have shown us that this assumption is false. There’s a lot we can do to prevent suicides. Sri Lanka is one of the most dramatic examples of this.
At the turn of the millennium, Sri Lanka had the second-highest suicide rate in the world (after Greenland). But look at the chart below: rates have fallen by almost two-thirds since then. Despite it having a growing population, the number of Sri Lankans dying from suicide has more than halved, saving thousands of lives every year.2
The biggest driver of this decline is something that most of us rarely think about: a reduction in self-poisonings from pesticides. This is a common method used in many low- to middle-income countries, where most suicides occur. The figures on this, like a lot of data on suicides globally, are uncertain. Many of the studies I’ll discuss in this article rely on data from police records, which tend to be an undercount due to stigma in reporting.3 But to give some sense of the magnitude of the problem: several studies estimate that pesticides are used in 14% to 20% of suicide deaths globally.4 That would mean 100,000 to 150,000 deaths each year.5
How did Sri Lanka reduce these deaths over the last 30 years? Many studies suggest that it was because the country banned some of the most toxic pesticides, while allowing them to be substituted for less harmful ones.6
In this article, I look at the evidence and arguments for banning highly toxic pesticides to reduce suicide deaths, including some of the concerns that these bans might raise.
The decline of pesticide suicide deaths in Sri Lanka
Let’s first look at the case study of Sri Lanka. Its suicide rates have fallen dramatically over the last 25 years. But why?
To answer this question, it’s helpful to look at the change in suicide methods over this period. A study by Duleeka Knipe and colleagues studied trends in suicide deaths in Sri Lanka from 1975 through to 2012.7 To get the breakdown by method and demographics, it relied on recorded data from the Department of Police’s Division of Statistics. Due to the stigma that is often attached to suicide deaths — and the challenges of collecting national data, especially in low-income countries in the 1980s or 1990s — it would be reasonable to expect that these deaths are a conservative estimate.
In the chart, you can see the suicide rate across different methods. What’s immediately clear is how dominant self-poisonings (mostly from pesticides) have been, but also the fact that this is where most of the decline in total suicide rates has come from. As recently as the late 1990s, 40 people per 100,000 were dying from self-poisonings each year. This has fallen by more than two-thirds to just over 10.
Again, some readers might be surprised that pesticides are the leading method of suicide. This is not a big issue in high-income countries, but it is in low- to middle-income countries. Pesticides have weaker regulations, meaning the general public can buy them like any other good. They’re often used in small-scale farming and stored on-site, which is frequently the family’s home. That means they’re easily accessible to many people.
What then caused this decline in pesticide poisoning deaths?
Many point to Sri Lanka’s ban on highly hazardous pesticides (HHPs) as the key driver. Pesticides are typically classified by the WHO and the UN’s Food and Agriculture Organization based on their hazards to human health and the environment. HHPs rate highly on this classification and are more fatal than most other pesticides if ingested.
Sri Lanka did not ban all HHPs in a single swoop. It gradually prohibited a range of HHPs over several decades. In the chart below, I’ve overlaid the dates of these bans onto the overall suicide rate trend. No single pesticide phase-out dropped rates by two-thirds alone. Instead, researchers attribute different substances to different parts of the overall trend.
The ban on parathion and methyl parathion in the 1980s is attributed to stopping a continued increase in suicide rates, which had been climbing for decades. The 1995 ban on WHO Class I toxicity pesticides led to the first sustained downturn. There was another step-change in 1998 due to the ban on endosulfan, and further bans on paraquat continued this decline into the late 2010s.
Researchers can also use more complex analyses to understand what role these bans had on the decline in suicide rates. These studies tend to find that they were a key driver.8
To be clear: this doesn’t mean they were the only reason for the reduction, but in a world without those bans, the fall in suicides would be much less steep, and many more people would be dying from pesticide poisonings every year.
Bans on the most toxic pesticides have reduced suicide deaths in other countries
Sri Lanka is not the only country to have experienced a decline in suicides from self-poisonings. In particular, this has been the case across several Asian countries. The chart shows the change in total suicide rates across a selection of countries in South and East Asia. These countries have banned at least some HHPs over this period (some also banned selected ones before 2000). As you can see, rates have fallen to varying degrees over the past few decades.
Again, the ban of HHPs is unlikely to be the only driver of this decline, but a few studies suggest it has been important.9 Even in countries where rates had stopped rising or were already falling, introducing a ban on particular HHPs often changed the rate of the decline.
It’s important to note that in some countries, these bans did not lead to a conclusive reduction in suicides. Nepal’s suicide rate, for example, has not changed, and studies suggest that the ingestion of banned pesticides is still one of the leading methods used.10 This suggests that these illegal substances are still entering and being used in the country.
So, the success of these bans in driving down suicide rates depended a lot on the context: how common self-poisonings already were; what pesticides were banned, and whether other highly toxic pesticides were still available; how stringently the bans were enforced; and how other risk factors for suicide were changing. However, across several countries, these bans appear to have had some positive impact on saving lives.
People often switch to other methods, but these tend to be less fatal
When I was looking at the initial research on this, I had some doubts that these bans could lead to a decline in total suicide rates.
First, Sri Lanka did not ban pesticides completely. It banned certain HHPs, which could be substituted for other chemical pesticides. If someone really wanted to die by suicide, wouldn’t they just consume the new pesticide anyway?
The answer is yes: many people did drink substituted pesticides. But, consuming these lower toxicity alternatives was much less deadly. A study from Nepal found that aluminum phosphide (a pesticide used before the ban) had a fatality rate of around 50%.11 That meant that half of those ingesting it would die. The pesticides used after the ban had a fatality rate of 7%. That’s seven times lower.
Some of the banned HHPs had even higher fatality rates than this, up to 80%. So even if the total number of people who consumed pesticides did not change at all, we would still expect the death rate to fall because they were much less likely to die as a result.
My second doubt was whether people simply switched from self-poisoning to another method. If someone were determined to die, we might expect them to seek out another way in the absence of toxic pesticides. For some people, this was the case. Earlier, we saw that in Sri Lanka, while suicide rates from self-poisonings had fallen a lot, there was an increase in suicide from hanging.12 But this increase was much smaller than the decline from pesticides, so it wasn’t the case that most, or even many, people made this switch. The decline in pesticide poisonings more than offset the increase in hangings, and so fewer people still died from suicide overall. This was also true in Bangladesh.
The size of this substitution effect can vary by country. Studies from India suggest a significant change in the methods used. After the pesticide endosulfan was banned nationwide in 2011, there was a strong decline in deaths from self-poisoning. But, over that same period, there was also a strong increase in suicides by hanging. By 2014, pesticide death rates were 48% lower than expected under a scenario without a ban.13 But the total suicide rate was only 10% lower. That’s because the rise in hanging had offset a substantial fraction of the lives “saved” from self-poisoning. This was particularly true for men, where total rates did not decline much. In women, there appeared to be a much smaller substitution effect.
My final doubt was whether removing HHPs would actually reduce suicide deaths, or simply delay them. If someone attempted suicide with a less toxic pesticide or a less fatal method, and did not die, wouldn’t they just try again? Broader research on suicide suggests that for most people, the answer is no.
An analysis combining the results of 177 studies over 30 years found that 1.6% of people who had attempted suicide tried again within one year, and 3.6% had tried again within five years.14 This suggests that more than 96% of people who attempt suicide and survive do not do so again in the next five years. If most people do not re-attempt suicide, then making sure that the method used in the first attempt has a low fatality risk could save many lives. In this case, that means removing access to highly toxic pesticides.
This leads to an important point underpinning some of the justification for these bans. People attempt suicide for a variety of reasons. Some have been struggling with mental health problems and suicidal ideation for a long time. A substantial fraction, though, does so as an impulsive act. Particularly during periods of acute crisis, some people attempt self-harm quickly as a way to alleviate the immediate emotional stress, without necessarily wanting to die. The attempt is not premeditated, and the time between the thought and the act can be incredibly short.15
For someone living in rural Sri Lanka, this might mean reaching for a highly toxic pesticide that is easily accessible at home. Interviews with Sri Lankans who survived self-poisoning attempts suggested that 85% chose their method based on accessibility: it was there and available in these moments of distress.16
If a large number of suicide attempts are the result of brief, impulsive acts, then it would make sense that removing the most fatal methods would make a difference. People would have a higher chance of survival and could get the help and support needed to prevent future attempts.
Could these pesticide bans create more harm and potentially increase suicides if they reduce food production?
So far, we’ve discussed pesticide use as a problem: they’re toxic and cost lives when consumed. However, when used effectively, pesticides can also bring important benefits in the form of food security, agricultural productivity, and farmer incomes.
Farmers can see vast amounts of their harvest wiped out if they lack ways to manage pests and disease. For many, that doesn’t just mean less food; it also means a big chunk of the year’s income is gone.
I’ve written previously about the benefits of agricultural technologies such as fertilizers, better seeds, pesticides, and irrigation for food production, poverty alleviation, and sparing natural habitat. These technologies have played a massive role in the dramatic rise in crop yields seen in countries like Sri Lanka, India, China, and Bangladesh. See the chart below.
A valid concern, then, is that taking these pesticides away would reduce crop yields and food production. That would not only be bad for food security, nutrition, and incomes, but possibly for suicide rates, too. If a large share of suicides is the result of impulsive acts due to acute stress, there is a reasonable argument that the repeated stress of crop failures, loss of income, and rural poverty could increase rates of suicide attempts.
After reviewing the scientific literature and data, I don’t think these bans have had significant negative impacts on productivity. What’s crucial is that there was no total ban on all pesticides; it was aimed at highly toxic ones, for which there were often less toxic substitutes or other ways to reduce pests.
Some of these replacements were direct chemical substitutes, which could perform just as well. In other cases, changes to farming practices have also been crucial, such as incorporating integrated pest management (which involves changes in crop rotations and resistant crop varieties). There is little evidence that, on aggregate, these bans have hindered crop yields. But that does not mean the substitution is always easy: in some cases, the substitute pesticide is more expensive; in others, it requires training and adaptations from farmers to use pesticides more efficiently.
Sri Lanka provides a good case study of both interventions; while they introduced a series of bans on specific HHPs over several decades, in 2021, the government also introduced an immediate ban on all fertilizer and pesticide imports.17 It gave several reasons for the ban. Sri Lanka was facing a severe foreign currency shortage and wanted to reduce the country’s spending on chemical imports. It also tried positioning itself as the first “organic nation” to tackle environmental pollution and health concerns about overusing these agricultural inputs. These health concerns were not specifically related to suicides from pesticides.
Let’s look at Sri Lanka’s rice yields since the 1960s. This is shown in the chart below. I’ve added lines flagging the dates of particular pesticide bans and the complete ban in 2021. Although there is always year-to-year variability in yields due to factors such as weather, there has been a fairly gradual increase in yields, particularly since the 1970s. There were no sudden drops in yields following any of the specific HHP bans. There was, however, a huge drop in yields over the 2021–2022 season, following the complete prohibition of fertilizer and pesticide imports (which made up most of the country’s supply).
This data matches the experiences of Sri Lankan farmers, many of whom experienced large declines in yields — sometimes more than 50% — as they were effectively forced to go organic overnight, without time to transition and develop new crop management strategies. The ban was so damaging and received so much backlash that the government reversed its decision in November 2021, just seven months after it was announced.
There is also evidence that banning less toxic pesticides does not help to reduce suicides from self-poisoning; therefore, blanket bans would not help to save lives from suicide and would hurt agricultural productivity in the process.18
As the study puts it: “These findings support the restriction of acutely toxic pesticides in resource-poor countries to help reduce hospitalization for and deaths from deliberate self-poisonings and caution against arbitrary bans of less toxic pesticides while more toxic pesticides remain available.”
Studies in other countries have found similar results. When toxic pesticides were banned in Bangladesh, pesticide deaths went down, but there was no clear impact on crop yields or food production.19
The same is true for India, which has had a steady, fairly linear yield increase for over 50 years.
Targeting the most toxic pesticides could be a cost-effective way to save lives in countries where this suicide method is common
To be clear: banning toxic pesticides is no substitute for addressing some of the underlying circumstances that drive people towards suicide, nor does it negate the need for investments in support for mental health. These bans are not going to stop self-poisonings completely. Despite a huge reduction in suicide rates in Sri Lanka, self-poisoning is still the leading method used.
A ban on highly hazardous pesticides in just 14 countries could save 28,000 lives each year and would cost only $30 million
But the research is convincing that banning selective HHPs has played a role in reducing the fatality of suicide attempts, saving thousands of lives each year in the process.
Some studies — although very few have modeled this — also suggest that it’s a relatively cost-effective intervention. This means it could save many lives, even in resource-constrained countries that don’t have large budgets to spend (which often means that mental health and suicide do not get attention at all).
In a study published in The Lancet, researchers estimate that a ban on HPPs in just 14 countries could save 28,000 lives each year from suicide, and would cost just $30 million in total.20 The intervention appears to be so cheap because very little sustained “delivery” is involved: it’s not a medical treatment that implies drug manufacturing, delivery, and healthcare staff. Nor does it involve a psychological intervention, delivered by trained personnel or an online resource. The main costs were the upfront effort of enacting national legislation and some ongoing resources for enforcing these bans. Cost-effectiveness, as we might expect, was far higher in countries where self-poisoning from pesticides was a leading method of suicide; this means focusing on these high-impact countries would save more lives.
In a separate analysis, the charity evaluator GiveWell suggested that one of the leading research organizations working on this problem — The Centre for Pesticide Suicide Prevention — was potentially among some of its most cost-effective interventions. However, it did stress that these analyses had to rely on a range of assumptions that make the conclusions less certain than the evidence base for other programmes.
Again, we should be clear that these interventions are only part of the solution. They are not a silver bullet to a varied and complex problem. But the evidence suggests that when carefully implemented, they have already saved many lives from suicide, and if implemented more broadly, could potentially save tens of thousands more, every year.
Acknowledgments
Many thanks to Edouard Mathieu, Saloni Dattani, and Simon van Teutem for feedback and suggestions on this article.
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Endnotes
The global suicide rate has fallen, though.
In 2000, the World Health Organization estimated that approximately 7,440 people died from suicide in Sri Lanka. In 2021, this was 3,175. That’s a reduction of around 57%.
Snowdon, J. (2019). Indian suicide data: What do they mean?. Indian journal of medical research, 150(4), 315-320.
The World Health Organization (WHO) estimates that 15% to 20% of suicides globally are the result of pesticide poisoning. That’s around 140,000 deaths each year.
A review across 108 countries estimated that around 14% of suicides from 2010 to 2014 were the result of pesticides. When accounting for underreporting, it puts this estimate at 20%. Suicide records from many countries — in particular, low-income countries in Sub-Saharan Africa — are often of poor quality, so these estimates are very uncertain.
Mew, E. J., Padmanathan, P., Konradsen, F., Eddleston, M., Chang, S. S., Phillips, M. R., & Gunnell, D. (2017). The global burden of fatal self-poisoning with pesticides 2006-15: systematic review. Journal of affective disorders, 219, 93-104.
It’s estimated that approximately 720,000 people die from suicide each year, but these figures are uncertain, and possibly an undercount.
Another factor, which we might expect to play a role, is that some more recent pesticides include ingredients called “emetics” which are designed to make people vomit. The idea is that people would then expel some toxic ingredients, reducing the risk of severe poisoning. The data on the effectiveness of these additions is limited. There are a few reported reasons why they’re less effective than expected. The first is that the person attempting suicide might ingest large amounts of pesticide, too much for emetics to counter. The second is that it can take some time for emetics to work and induce vomiting. By then, much of the active ingredient can already have been absorbed.
Eddleston, M. (2022). Evidence for the efficacy of the emetic PP796 in paraquat SL20 formulations–a narrative review of published and unpublished evidence. Clinical Toxicology, 60(10), 1163-1175.
Deuster, E., Tomenson, J. A., Mohamed, F., Gawarammana, I., Buckley, N. A., Wilks, M. F., & Eddleston, M. (2023). Dose ingested, vomiting, and outcome in patients ingesting a standard paraquat 20SL formulation. Clinical Toxicology, 61(1), 29-38.
Knipe, D. W., Metcalfe, C., Fernando, R., Pearson, M., Konradsen, F., Eddleston, M., & Gunnell, D. (2014). Suicide in Sri Lanka 1975–2012: age, period and cohort analysis of police and hospital data. BMC Public Health, 14, 1-13.
Knipe, D. W., Chang, S. S., Dawson, A., Eddleston, M., Konradsen, F., Metcalfe, C., & Gunnell, D. (2017). Suicide prevention through means restriction: Impact of the 2008-2011 pesticide restrictions on suicide in Sri Lanka. PloS one, 12(3), e0172893.
Cha, E. S., Chang, S. S., Choi, Y., & Lee, W. J. (2020). Trends in pesticide suicide in South Korea, 1983–2014. Epidemiology and psychiatric sciences, 29, e25.
Cha, E. S., Chang, S. S., Gunnell, D., Eddleston, M., Khang, Y. H., & Lee, W. J. (2016). Impact of paraquat regulation on suicide in South Korea. International journal of epidemiology, 45(2), 470-479.
Gunnell, D., Knipe, D., Chang, S. S., Pearson, M., Konradsen, F., Lee, W. J., & Eddleston, M. (2017). Prevention of suicide with regulations aimed at restricting access to highly hazardous pesticides: a systematic review of the international evidence. The Lancet global health, 5(10), e1026-e1037.
Bonvoisin, T., Utyasheva, L., Knipe, D., Gunnell, D., & Eddleston, M. (2020). Suicide by pesticide poisoning in India: a review of pesticide regulations and their impact on suicide trends. BMC public health, 20, 1-16.
Cha, E. S., Chang, S. S., Gunnell, D., Eddleston, M., Khang, Y. H., & Lee, W. J. (2016). Impact of paraquat regulation on suicide in South Korea. International journal of epidemiology, 45(2), 470-479.
Chowdhury, F. R., Dewan, G., Verma, V. R., Knipe, D. W., Isha, I. T., Faiz, M. A., ... & Eddleston, M. (2018). Bans of WHO class I pesticides in Bangladesh—suicide prevention without hampering agricultural output. International journal of epidemiology, 47(1), 175-184.
Yan, Y., Jiang, Y., Liu, R., Eddleston, M., Tao, C., Page, A., ... & Liu, S. (2023). Impact of pesticide regulations on mortality from suicide by pesticide in China: an interrupted time series analysis. Frontiers in psychiatry, 14, 1189923.
Utyasheva, L., Sharma, D., Ghimire, R., Karunarathne, A., Robertson, G., & Eddleston, M. (2021). Suicide by pesticide ingestion in Nepal and the impact of pesticide regulation. BMC public health, 21, 1-11.
Moebus, S., & Boedeker, W. (2021). Case Fatality as an Indicator for the Human Toxicity of Pesticides — A Systematic Scoping Review on the Availability and Variability of Severity Indicators of Pesticide Poisoning. International journal of environmental research and public health, 18(16), 8307.
Knipe, D. W., Chang, S. S., Dawson, A., Eddleston, M., Konradsen, F., Metcalfe, C., & Gunnell, D. (2017). Suicide prevention through means restriction: Impact of the 2008-2011 pesticide restrictions on suicide in Sri Lanka. PloS one, 12(3), e0172893.
Bonvoisin, T., Utyasheva, L., Knipe, D., Gunnell, D., & Eddleston, M. (2020). Suicide by pesticide poisoning in India: a review of pesticide regulations and their impact on suicide trends. BMC public health, 20, 1-16.
These rates were slightly lower in Asia, where most pesticide-related deaths still happen today.
Carroll, R., Metcalfe, C., & Gunnell, D. (2014). Hospital presenting self-harm and risk of fatal and non-fatal repetition: systematic review and meta-analysis. PloS one, 9(2), e89944.
This can be 10 minutes or less in many patients.
Deisenhammer, E. A., Ing, C. M., Strauss, R., Kemmler, G., Hinterhuber, H., & Weiss, E. M. (2009). The duration of the suicidal process: how much time is left for intervention between consideration and accomplishment of a suicide attempt?. Journal of Clinical Psychiatry, 70(1), 19.
Conner, K. R., Phillips, M. R., Meldrum, S., Knox, K. L., Zhang, Y., & Yang, G. (2005). Low-planned suicides in China. Psychological medicine, 35(8), 1197-1204.
Eddleston, M., Karunaratne, A., Weerakoon, M., Kumarasinghe, S., Rajapakshe, M., Rezvi Sheriff, M. H., ... & Gunnell, D. (2006). Choice of poison for intentional self-poisoning in rural Sri Lanka. Clinical Toxicology, 44(3), 283-286.
Drechsel, P., Madhuwanthi, P., Nisansala, D., Ramamoorthi, D., & Bandara, T. (2025). On the feasibility of an agricultural revolution: Sri Lanka’s ban of chemical fertilizers in 2021. Food Security, 1-18.
Noghrehchi, F., Dawson, A. H., Raubenheimer, J., Mohamed, F., Gawarammana, I. B., Eddleston, M., & Buckley, N. A. (2024). Restrictions on pesticides and deliberate self-poisoning in Sri Lanka. JAMA network open, 7(8), e2426209-e2426209.
Chowdhury, F. R., Dewan, G., Verma, V. R., Knipe, D. W., Isha, I. T., Faiz, M. A., ... & Eddleston, M. (2018). Bans of WHO class I pesticides in Bangladesh—suicide prevention without hampering agricultural output. International journal of epidemiology, 47(1), 175-184.
Lee, Y. Y., Chisholm, D., Eddleston, M., Gunnell, D., Fleischmann, A., Konradsen, F., ... & Van Ommeren, M. (2021). The cost-effectiveness of banning highly hazardous pesticides to prevent suicides due to pesticide self-ingestion across 14 countries: an economic modelling study. The Lancet global health, 9(3), e291-e300.
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Hannah Ritchie (2025) - “Bans on highly toxic pesticides could be an effective way to save lives from suicide” Published online at OurWorldinData.org. Retrieved from: 'https://ourworldindata.org/pesticide-bans-suicide-prevention' [Online Resource]BibTeX citation
@article{owid-pesticide-bans-suicide-prevention,
author = {Hannah Ritchie},
title = {Bans on highly toxic pesticides could be an effective way to save lives from suicide},
journal = {Our World in Data},
year = {2025},
note = {https://ourworldindata.org/pesticide-bans-suicide-prevention}
}
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