The present invention relates to a non-toxic composition containing one or more cysteine compounds selected from L- or D-cysteine, N-acetyl cysteine, and the pharmaceutically acceptable salts thereof, for decreasing the risk of a subject contracting cancer of the stomach, the small intestine and the colon, by locally binding aldehydes present in the stomach, and optionally also separately the aldehydes carried to the small intestine or the colon, or both, whereby the composition is formulated with the help of two or more additives into controlled-release tablets containing at least one additive selected from cationic and gel-forming polymers, which tablets are formed from two or more separate layers with different release profiles, whereby the cysteine compounds are added both into the inner layer(s) and into the tablet material surrounding these.
