Following oral administration of 14C-aminoglutethimide (Orimeten), male mice excreted 75% and female mice 59% of the administered dose during 24 h. After 72 h, elimination was essentially complete in male mice, whilst recovery from female mice was 74%. As assessed by quantitative assay and whole-body autoradiography, a wide distribution of radioactivity was found with high concentrations of radioactivity occurring only in the bile, gastro-intestinal tract and liver at early times. Residual (72 h) tissue levels of radioactivity were less than 1 microgram equiv. of 14C-aminoglutethimide/g tissue. Metabolite profiles in urine, tissues and faeces showed extensive metabolism of the drug in a pattern similar to that found in the rat.