Innovation summary

Ingestion of pesticides in acts of self-harm accounts for one third of the global burden of suicide. In Asia there are at least 300,000 deaths from pesticide self-poisoning every year 2.

The goal of this innovation is to regulate or ban the sale of specific classes of agricultural pesticides that are highly toxic to humans in order to reduce the extremely high suicide rate in rural areas of developing nations. National and international policies implementing this innovation would cause a rapid, major and sustained fall in suicides that would be recognized both locally and globally.

Impact summary

  • The total number of suicides in Sri Lanka fell by 50% from 1996-2005 compared to 1986-1995 – a reduction of approximately 19,800 suicides
  • Only 1% of people who survive a suicide attempt take their lives in the following year
  • This innovation is very low cost for the government, with the bulk of the costs felt by the pesticide industry for developing new products.

"Members of agricultural communities in low- and middle-income countries are heavily over-represented in the suicide death toll related to pesticides. Controlling access to pesticides is not only critical in reducing self-directed violence, it is key to preventing  unintentional poisoning and terrorism. International conventions attempt to manage hazardous substances; however, many highly toxic pesticides are still widely used."


-WHO 2009: Guns, knives, and pesticides : reducing access to lethal means1

Innovation details

Suicide is one of the leading causes of premature mortality worldwide. The World Health Organization (WHO) estimates that there are approximately one million suicides every year; rates are particularly high in rural Asia. Ingestion of pesticides in acts of self-harm accounts for one third of the global burden of suicide. These deaths are readily preventable as research shows that restricting access to highly lethal methods of suicides saves lives.1

This innovation aims to ban the sale of the agricultural pesticides that are most toxic when ingested by humans: namely all WHO toxicity Class I pesticides. In addition, following research on the local epidemiology of fatal pesticide poisoning, the ban of WHO toxicity Class II pesticides that are local problems for suicide (in Sri Lanka: endosulfan, paraquat, and organophosphorus insecticides such as dimethoate and fenthion).1

By providing advice to farmers on locally acceptable alternative practices (e.g. IPM) or less toxic pesticides, and by working with industry, such bans in Sri Lanka have been shown to be acceptable to farmers and to have minimal effect on agricultural costs or crop yields.

There is strong evidence that restriction of access to commonly used, highly lethal methods of suicide leads to an overall reduction in suicides. This is because suicide attempts are often made impulsively in moments of crisis when the ready availability of highly-lethal methods means the suicide attempt is more likely to result in death. Thus in rural areas of developing countries around 10% of episodes of self-poisoning are fatal because of the high toxicity of commonly used pesticides (e.g. the case fatality for Paraquat self-poisoning is 50-60%).  In contrast in the UK, where paracetamol is the substance most frequently ingested by people who attempt suicide, death rates are low because the case fatality following ingestion of paracetamol is <0.5%.

The other good example of how restriction of access to means of suicide can save lives comes from Norman Kreitman’s assessment of the impact on suicide rates of changes in the UK’s domestic gas supply in the 1950s-60s. In the 1950s domestic gas poisoning accounted for almost half of all suicides in the UK. The high carbon monoxide content of domestic gas accounted for it being highly lethal. In the 1960s, the UK’s domestic gas supply changed from coal gas (with its high carbon monoxide content) to natural gas (with very low carbon monoxide levels). This made suicide by domestic gas poisoning almost impossible. Rates of domestic gas poisoning fell to almost zero by the 1970s and, crucially, there was no compensatory rise in suicides using other methods – there was no “method substitution” to other equally lethal methods. Several thousand lives were saved.3

The particularly successful features of the innovation are:

  • The intervention is low cost and simple to implement by a decision taken by the Ministry of Agriculture
  • By saving lives, it allows patients to subsequently be helped with psycho-social support or psychiatric treatment 
  • In addition to saving lives, the innovation markedly reduces health care costs: treatment of patients with pesticide self-poisoning often necessitates several weeks of expensive intensive care in already overstretched hospitals 
  • While bans on highly toxic pesticides do not stop people self-poisoning, the alternative products that people then take (such as medicines or newer pesticide products) are much less toxic in overdose so are  less likely to lead to death or prolonged periods of hospitalization

Key drivers

Political Will 

  • A strong political will and public desire to reduce the number of suicides in Sri Lanka, as reflected in the President setting up a Presidential Commission in 1995 to address the issue
  • A Registrar of Pesticides and pesticide regulatory system that understood the problem, considered it to be within their remit, and recognized the simplicity of the solution


  • Good research evidence identifying the burden of the problem and the key pesticides to ban
  • A well-established line of communication between the Pesticide Registrar, clinicians seeing poisoned patients, and researchers addressing this problem


  • A tradition of the retail sector adhering to government regulations exists


  • Modest pesticide industry lobbying against some of the pesticide bans
  • Concerns about impact on crop yield – ameliorated by research


Bans of some highly toxic pesticides in agriculture have been implemented in a few Asian and South American countries but these have not usually been in response to suicides. The approach has also not been comprehensive, monitored and iterative, aiming towards a target of less deaths from suicide.

In Asia, there are at least 300,000 deaths from pesticide self-poisoning every year. National and international policies implementing this innovation would cause a rapid, major and sustained fall in suicides across the region that would be recognized both locally and globally.

The future plans are to continue an iterative process, to monitor trends in pesticide suicides in Sri Lanka and to respond to these findings by further pesticide regulation. To work with national ministries and international bodies concerned by the issue across the region to provide data on this approach.



Evaluation methods

The intervention has been evaluated by analyzing long term trends in suicides by pesticide poisoning and  overall suicide rates in Sri Lanka. Favorable changes in underlying trends in pesticide suicides followed the Registrar of Pesticide’s regulatory interventions. These were NOT offset by use of alternative methods of suicide and so were associated with marked declines in fatalities.

Two main sources of data were used: i) Sri Lanka’s rich national suicide mortality statistics which record the annual numbers of suicides using different methods and in different age/sex groups; ii) manual review of patient notes and intensive care unit records from hospitals in Sri Lanka.

The evaluations showed a reduction in total suicides and falls in case fatality following pesticide ingestion. 

Cost of implementation

The innovation has not yet been formally costed in Sri Lanka. This work is underway.

The cost to the government will relate to the expenses of running the Office of the Registrar of Pesticides, the process of developing the new agricultural policies and guidelines, and providing information to the pesticide industry, the Customs, import control authority, agricultural extension services and subsequently to the farmers and pesticide vendors. The ban also has to be monitored to make sure it is followed at the retail level.

There will be costs to the pesticide industry for developing and marketing new products; however, this process is already on-going for other markets, markedly reducing the direct costs. In addition, if any ban is implemented immediately, there will be costs to vendors and industry for taking pesticides out of shops and either destroying them or moving them to another market. However, all Sri Lankan bans have been implemented over 2-3 years, allowing stocks to gradually fall as they are not replaced.

Impact details

As a direct result of the innovation (banning all WHO toxicity Class I pesticides followed three years later by the problematic WHO Class II toxicity pesticide endosulfan) the total number of suicides in Sri Lanka fell by 50% from 1996-2005 compared to 1986-1995 – a reduction of approximately 19,800 suicides.

Previous bans in the 1980s of a few specific WHO toxicity Class I organophosphorus insecticides, such as methyl-parathion, had already stopped the exponential rise in suicides seen in the 1970s and early 1980s, saving many thousands of lives. Recent bans of dimethoate, fenthion and paraquat around 2008 are bringing the number of suicide deaths down even further1.


1.  WHO (2009): Guns, knives, and pesticides : reducing access to lethal means. Geneva: World Health Organisation. (accessed: 26th November 2013)

2. Eddleston M and Phillips MR (2004) Self poisoning with pesticides. British Medical Journal, 328: 42-44. (access: 26th November 2013)

3. Kreitman N (1976) The coal gas story. British Journal of Social and Preventive Medicine, 30:86-93 (Accessed: 26th November 2013)

4. Gunnell D et al. (2007) The global distribution of fatal pesticide self-poisoning: systematic review. BMC Public Health, 7: 357. (Accessed: 26th November 2013)]

5. Manuweera G et al. (2008) Do targeted bans of insecticides to prevent deaths from self-poisoning result in reduced agricultural output? Environmental Health Perspectives, 116: 492-495. (Accessed: 14th July 2014)



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