Pesticide exposure can cause many different health effects, from acute problems such as dermatitis and asthma exacerbation to chronic problems such as chronic obstructive pulmonary disease and cancer. The resulting clinical presentations are undifferentiated, and specific knowledge of the links to environmental exposures is often required for effective diagnosis. In this article we illustrate the use of the CH2OPD2 mnemonic (Community, Home, Hobbies, Occupation, Personal habits, Drugs and Diet), a history-taking tool that assists physicians in quickly identifying possible environmental exposures. We also provide clinical information on the epidemiology, clinical presentations, treatment and prevention of pesticide exposures.