Mitomycin analogues were tested against metacestode stages of Hymenolepis microstoma and H. nana developing in Tribolium confusum. The effects of the mitomycins varied according to both the drug and the species of the parasite. In general, the most effective compound was mitomycin C, followed by mitomycin A and then by mitomycin F. The efficacy of drugs improved further when sodium bicarbonate was added to the diet.