Naturally occurring compounds belonging to two chemical groups were studied for their capacities to inhibit N-nitrosodiethylamine (NDEA)-induced carcinogenesis in female A/J mice. One group consists of organosulfur compounds found in Allium species, including garlic, onions, leeks, and shallots, and the other, two monoterpenes, i.e., D-limonene and D-carvone. In an initial experiment, in which ...