Inhibition of some spontaneous tumors by 4-hexylresorcinol in F344/N rats and B6C3F1 mice.

4-Hexylresorcinol (4-HR) is used as an anthelmintic and antiseptic in human and veterinary medicine. Toxicology and carcinogenesis studies were conducted by administering 4-HR in corn oil by gavage at 0, 62.5, or 125 mg/kg to F344 rats and B6C3F1 mice of each sex for 2 years. The nonneoplastic lesions associated with 4-HR exposure were nephropathy and osteosclerosis in dosed male and female mice. The only evidence of neoplasia associated with 4-HR was marginally increased incidences of adrenal gland pheochromocytomas and harderian gland tumors in male mice. Decreases were observed in the incidences of mononuclear cell leukemia in dosed male and female rats, hepatocellular adenomas or carcinomas in dosed male mice, and circulatory system tumors in high-dose male and female mice. These negative tumor trends in rats and mice, along with an indication of reduced overall incidences of benign and malignant tumors in treated groups compared to controls, suggest that 4-HR may deserve further study as a possible antineoplastic agent.