Promoting action of croton oil on gastrocarcinogenesis by N-methyl-N'-nitro-N-nitrosoguanidine in rats.

The promoting effect of croton oil on gastrocarcinogenesis by MNNG was examined in male Wistar rats. Gastric carcinomas were found in five of 10 rats given 83 micrograms/ml MNNG for three months and then 0.02% croton oil with 0.5% Tween 60 as solvent for nine months. No gastric carcinomas were found in rats given MNNG for three months and then Tween 60 only for nine months. The incidence of gastric carcinomas in these two groups was significantly different (p less than 0.05). No tumors were found in rats given only croton oil with Tween 60.