Diquat is also known as Linon. It is white or yellow crystal, and belongs to medium poisonous herbicide. The lethal dose of dibromide to human is about 6-12 g. Diquat is degraded by bacterial action in gastrointestinal tract, so it is less absorbed through gastrointestinal tract. After absorption, it is distributed to organs and tissues of the whole body with blood flow, among which the concentration in liver and kidney is higher. Its metabolites are mainly excreted through the kidneys and bile.1.Oral poisoning: nausea, vomiting, abdominal pain, diarrhea, oral ulceration, etc.2.Central nervous system damage: manifestation of dizziness, headache, euphoria, restlessness and disorientation, etc.; in severe cases, convulsions and coma may occur.3.Toxic liver disease occurs in some patients. In severe cases, acute renal failure occurs.4. Skin and membrane damage manifests dermatitis, nosebleed, conjunctiva and cornea burns.