ARTICLES Long-term Feeding of Sodium Saccharin to Nonhuman Primates: Implications for Urinary Tract Cancer

Background: It was observed in the early 1970s that saccha-rin produced bladder cancer in rats. However, it has been unclear whether sodium saccharin when consumed by hu-mans poses a substantial carcinogenic hazard. Numerous epidemiologic studies have not shown any evidence of in-creased urothelial proliferation associated with ingestion of sodium saccharin. Purpose: Our purpose was to determine the effects of long-term feeding of sodium saccharin to three species of nonhuman primates. Methods: Twenty monkeys of three species (six African green, seven rhesus, six cynomol-gus, and one hybrid [of rhesus male and cynomolgus female parentage]) were treated with sodium saccharin (25 mg in the diet/kg body weight daily for 5 days a week) beginning within 24 hours after birth and continuing for up to 24 years. Sixteen monkeys (seven rhesus and nine cynomolgus) serve