Another set of major health disruptors is pesticides, whose effect on our health can be deadly. Pesticides are chemical compounds that are used to kill pests that damage crops, including insects, rodents, fungi, and unwanted plants (weeds). Over one thousand different pesticides are used around the world today. By their nature, they are potentially toxic to other organisms, including humans. They can have both acute and chronic health effects, and are among the leading causes of death by self-poisoning.