Paraquat poisoning

Paraquat (dipyridylium) is a highly toxic weed killer once promoted by the United States for use in Mexico to destroy marijuana plants. Research found that this herbicide was dangerous to workers who applied it to the plants.

This article discusses the health problems that can occur from swallowing or breathing in Paraquat.


In the United States, Paraquat is classified as "restricted commercial use," and people must obtain a license to use the product.

Breathing in Paraquat may cause lung damage and can lead to a disease called Paraquat lung. Paraquat causes damage to the body when it touches the lining of the mouth, stomach, or intestines. You can get sick if Paraquat touches a cut on your skin. Paraquat may also damage the kidneys, liver, and esophagus.

If Paraquat is swallowed, death can rapidly occur. Death may occur from a hole in the esophagus, or from acute inflammation of the mediastinum, the area that surrounds the major blood vessels and airways in the middle of the chest.

Chronic exposure to Paraquat may cause pulmonary fibrosis, a stiffening of the lung tissue.


  • Burns in throat
  • Coma
  • Difficulty breathing
  • Nosebleed
  • Seizures
  • Shock
  • Shortness of breath
  • Sore throat
  • Stomach pain
  • Vomiting

Exams and Tests

You will be asked if you have been exposed to Paraquat.

Blood and urine tests will be done to determine how much Paraquat is in your system. Other tests that may be done include:

  • Arterial blood gases (measures of oxygen, carbon dioxide, and acid-base balance)
  • BUN and creatinine (kidney function tests)
  • Chem-20
  • Chest x-ray
  • Lung function tests
  • Urinalysis
  • Urine toxicology screen


There is no specific treatment for Paraquat poisoning. The goal is to relieve symptoms and treat complications (supportive care).

Remove all contaminated clothing.

If the chemical touched your skin, wash the area with soap and water for 15 minutes,without scrubbing hard, so as not to cause abrasions which will allow greater absorption of the toxin.

If there has been contamination of the eyes, flush them with water for 15 minutes.

If you have swallowed Paraquat, you should receive activated charcoal as quickly as possible. Sicker patients may need a procedure called hemoperfusion, which filters the blood through charcoal to try to remove Paraquat from the lungs.

Outlook (Prognosis)

The outcome depends on the severity of exposure. Some people may develop mild breathing-related symptoms and have a full recovery, while others may have permanent changes in the lungs. If a person swallowed the poison, death is likely without immediate medical care.

Possible Complications

  • Acute respiratory distress syndrome
  • Holes in the esophagus
  • Inflammation of the area between the lungs (mediastinitis)
  • Kidney failure
  • Scarring of the lungs (pulmonary fibrosis)

When to Contact a Medical Professional

If you believe you have been exposed to Paraquat, you should seek medical care immediately.

The National Poison Control Center (1-800-222-1222) can be called from anywhere in the United States. This national hotline number will let you talk to experts in poisoning. They will give you further instructions.

This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

Take the container with you to the hospital, if possible.

See: Poison control center - emergency number


Avoid exposure to Paraquat.

Alternative Names

Paraquat lung