Effects of onion extract on the development of hamster buccal pouch carcinomas as expressed in tumor burden.

One-hundred male, young-adult Syrian hamsters (Mesocricetus auratus) were divided into five equal groups of 20 animals each. Groups 1, 2, and 3 were painted three times a week in the left buccal pouches with a 0.5% solution of 7,12-dimethylbenz[a]anthracene (DMBA) in mineral oil. Group 1 animals also received a 20% onion extract in their drinking water and were also painted in left buccal pouches three times a week with a 50% onion extract in mineral oil. Group 2 animals received the onion extract in their drinking water, but they received only mineral oil in buccal pouches as a control for the painting with onion extract in mineral oil. Group 3 animals received DMBA but no onion extract. Group 4 animals received onion extract but no DMBA, and Group 5 animals were left untreated. Onion extract was found to significantly delay tumor formation in Groups 1 and 2 compared with Group 3 DMBA controls.