Pyridine can cause chemical burns on contact with the skin and its fumes may be irritating to the eyes or upon inhalation. Pyridine depresses the nervous system giving symptoms similar to intoxication with vapor concentrations of above 3600 ppm posing a greater health risk. The effects may have a delayed onset of several hours and include dizziness, headache, lack of coordination, nausea, salivation, and loss of appetite. They may progress into abdominal pain, pulmonary congestion and unconsciousness. The lowest known lethal dose (LD) for the ingestion of pyridine in humans is 500 mg·kg.