Paraquat lung is a lung disease caused by the weed killer Paraquat (dipyridylium).

Paraquat 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.

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. 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.

• shortness of breath
• difficulty breathing
• breathing requires increasing effort
• sore throat
• vomiting or GI distress

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

Tests to diagnose Paraquat lung include:

• arterial blood gasses
• X-ray of the chest
• electrolytes (see chem-20)
• urinalysis
• BUN
• creatinine
• pulmonary function tests
• urine toxicology screen

There is no specific treatment for Paraquat poisoning. The goal is to relieve symptoms and address any complications that arise.

The outcome depends on the severity of exposure. The affected person may develop mild breathing-related symptoms with full recovery, or they may have permanent changes in the lungs, or if the person received a large dose at once (as with ingestion), death may occur.

• ARDS
• Pulmonary fibrosis
• Esophageal perforation
• Mediastinitis

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

Avoid exposure to paraquat.