ABSTRACT
Paraquat (1, 1'-dimethy1-4, 4'-dipyridylium dichloride) was administered to Wister rats orally at100mg/kg, 50mg/kg and 25mg/kg.<BR>Death generally occured in1-5days, many animals of the group administered at 100mg/kg died within 24 hours.<BR>Loss of body weight began on the second day after paraquat ingestion.<BR>The lung became the organ of highest concentration of paraquat, that reached maximum level with in 2 hours and was eliminated approximately 62-82% 24 hours later.<BR>Biochemical studies gave high levels of serum LDH and GOT, but no abnormalities were detected hematologically.<BR>Histopathological examinations has shown that the lung was the target organ of the paraquat poisoning. At the early stage, there were atelectasis, pulmonary edema and disintegration of the alveolar epithelium. These were followed by an infiltration of fibroblasts and glandular proliferation of the terminal bronchiolar epithelium. Parenchymal damages of the heart, liver and kidney were most dominant in 24 hours after paraquat ingestion, from which animals recovered subsequently.