Definition of Paraquat

Paraquat: A toxic chemical widely used as an herbicide (plant killer), primarily for weed and grass control. Paraquat is highly poisonous. It was first produced for commercial purposes in 1961.

The most likely route of exposure to paraquat leading to poisoning is ingestion (swallowing). Paraquat can be easily mixed with food, water, or other beverages. Paraquat poisoning is also possible after skin exposure.

The extent of poisoning caused by paraquat depends on the amount, route, and duration of exposure and the person's condition of health at the time of the exposure. Paraquat causes direct damage when it comes into contact with the lining of the mouth, stomach, or intestines. After paraquat enters the body, it is distributed to all areas of the body. Toxic chemical reactions occur throughout many parts of the body, primarily the lungs, liver, and kidneys.

If a person survives the toxic effects of paraquat poisoning, long-term lung damage (scarring) is highly likely. Other long-term effects may also occur, including kidney failure, heart failure, and esophageal strictures (scarring of the swallowing tube that makes it hard for a person to swallow). People with high-dose exposure to paraquat are not likely to survive. See also: Paraquat lung.