Paraquat is one of the most widely used herbicides in the US for the control of weeds in many agricultural and non-agricultural settings and is also used as a defoliant on crops, such as cotton, prior to harvest. Paraquat is a safe and effective herbicide when used as directed on the label. However, for a number of reasons, suicide with agrochemicals is a tragic and regrettable social problem particularly in some less developed countries. Agrochemicals are also occasionally involved in cases of accidental ingestion, most often as a consequence of individuals breaching recommended practice by decanting product into unlabeled beverage bottles.​ Paraquat is the active ingredient of Gramoxone, which is used to control weeds and grasses and as a harvest aid desiccant and/or defoliant.

It is a restricted-use pesticide due to acute toxicity and is for retail sale to and only for use by certified applicators. The product is toxic to humans as well as wildlife, is mildly corrosive to aluminum, and produces hydrogen gas which may form a highly combustible gas mixture in the presence of aluminum. It is commonly used as a burn down product, to control grass cover crops or volunteer cereals, and may provide control of perennial and annual broad-leaf weeds.


Paraquat dichloride, commonly referred to as “paraquat,” is one of the most widely used herbicides in the United States. Since paraquat’s first registration, EPA has reviewed and reassessed its safety and uses, including undergoing registration review, a program that re-evaluates each registered pesticide on a 15-year cycle.  

In July 2021, after receiving and considering public comments on the paraquat proposed interim decision, EPA released the interim decision for registration review. As part of this action, EPA is requiring mitigation measures to reduce risks associated with paraquat in order to protect human health and the environment.

Features of Paraquat Herbicide

  • Paraquat is a toxic chemical that is widely used as an herbicide (plant killer), primarily for weed and grass control.
  • In the United States, paraquat is available primarily as a liquid in various strengths. The US Environmental Protection Agency classifies paraquat as “restricted use.” This means that it can be used only by people who are licensed applicators.
  • Because paraquat is highly poisonous, the form that is marketed in the United States has a blue dye to keep it from being confused with beverages such as coffee, a sharp odor to serve as a warning, and an added agent to cause vomiting if someone drinks it. Paraquat from outside the United States may not have these safeguards added.

Where paraquat is found and how it is used

  • Paraquat was first produced for commercial purposes in 1961.
  • Worldwide, paraquat is still one of the most commonly used herbicides.
  • In the United States, due to its toxicity, paraquat is available for use only by commercially licensed users.

Uses/benefits of Paraquat Herbicide

Commercial farmers and other agricultural workers in the United States have been using paraquat to control invasive weeds and grasses since 1964. Applicators spray it on commercial crops such as corn, soy and cotton. Because of its toxicity, the EPA limits the herbicide’s use to licensed applicators for commercial use. There are no paraquat products licensed for use by homeowners.

How paraquat works

  • The extent of poisoning caused by paraquat depends on the amount, route, and duration of exposure and the person’s health condition 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. Paraquat causes toxic chemical reactions to occur throughout many parts of the body, primarily the lungs, liver, and kidneys.
  • Cells in the lung selectively accumulate paraquat likely by active transport.

Short-Term Side Effects

The first symptoms of acute poisoning through ingestion are immediate and start with pain and swelling in the mouth and throat. When the chemical enters the stomach, it causes gastrointestinal problems such as diarrhea, vomiting and nausea.

Short-term symptoms and side effects can occur within hours to several weeks after exposure and can be fatal.Short-term paraquat exposure side effects include:

  • Coma
  • Confusion
  • Fast heart rate
  • Fluid in the lungs
  • Gastrointestinal problems (nausea, vomiting, diarrhea)
  • Heart failure
  • Kidney failure
  • Liver failure
  • Lung scarring
  • Muscle weakness
  • Respiratory failure
  • Seizures
  • Swelling

Long-term health effects

  • 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 large ingestions of paraquat are not likely to survive.

Prices of Paraquat Herbicide

$67.70 – $ 160.00

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