Toxicological and pharmacological studies on dihydrorotenone.

Data are given on the acute and chronic toxicity of dihydrorotenone to rats. Single oral doses of 1.5 Gm./Kg. were nontoxic. Continued oral ingestion of dihydrorotenone by the drug diet method for approximately 400 days produced significant growth retardation of rats on diets containing 0.004 per cent (40 p.p.m.) or more. On diets containing 0.004 through 0.032 per cent (40 through 320 p.p.m.), a progressive loss of liver cell basophilia and dispersal of liver cell granules were observed. On the lower dietary levels (0.001 and 0.002 per cent; 10 and 20 p. p. m.), no significant histological changes were observed in the liver or other organs.