A novel laboratory anticestode assay was developed using Hymenolepis diminuta in the hamster. The commercial anticestode compounds, praziquantel, bunamidine, and niclosamide were active against patent infections of Hymenolepis diminuta in golden hamsters (Mesocricetus auratus) when given orally at 3.125, 100, and 200 mg/kg, respectively. The gastrointestinal nematode anthelmintics, cambendazole and mebendazole, were active at 50 mg/kg. Rafoxanide (fasciolicide) was active at 25 mg/kg, the lowest level tested. The coccidiostat, nicarbazin, was active at experimental levels (800 mg/kg and up). The anthelmintic–ectoparasiticide (endectocide), ivermectin, was inactive against the tapeworm at 0.5 mg/kg, as expected.