PROBLEMS TO BE SOLVED: To provide a highly safe lapactic agent that exhibits a sufficient lapactic effect such as the promotion of catharsis even by the intake of a small quantity, and a food product containing such a lapactic agent having a lapactic effect. MEANS TO SOLVE THE PROBLEMS: A lapactic agent comprising (A) a basic polymer and/or the salt thereof, and (B) a dietary fiber, wherein (A) a basic polymer and/or the salt thereof is at least one selected from the group consisting of polyvinylamine, polyallylamine, polyethyleneimine, polyvinylpyridine, poly (N,N-dimethylaminoethyl acrylate), .epsilon.-polylysine, a copolymer formed from a monomer having an amino group selected from the group consisting of vinylamine, allylamine, vinylpyridine, vinylmethylimidazole, N,N-dimethylaminoethyl acrylate, and N,N-dimethylaminopropyl acrylate; and a salt of these polymers; and a food product containing such a lapactic agent.