Study on the Maximum Non - Effect Dose of Phenmedipham

[Objective] To study the sub - chronic toxicity of Phenmedipham on rats and evaluate its maximum non - effect dose. [Methods]80 SD healthy rats were randomly divided into 4 groups; experiments were carried out according to the GB 15670 - 1995 Toxicological Test Methods for Pesticides Registration . [Results]Weight increase and food utility in the feedstuff group (5 000 mg/kg) were obviously lower than that of the control group; the lung - weight ratio, spleen - weight ratio and liver - weight ratio were all higher than that of the control group; the total amount of feedstuff intake, weight increase, food utility in the feedstuff group (15 000 mg/kg) were obviously lower than that of the control group, the brain - weight ratio, spleen - weight ratio, liver - weight ratio and thymus - weight ratio were all higher than that of the control group. The histopathological examination indicted that the rate of pathological changes in the kidney and lung of the feedstuff groups (5000 and 1500 mg/kg groups) was rather high.[Conclusion]The maximum non - effect dose of the Phenmedipham was (133.06±13.11) mg/(kg·d) on female rats and (121.52±13.29) mg/(kg·2d) on male rats.