Mebendazole works well, but its effects are limited strictly to the GI tract as it is poorly absorbed. Problem with this is obviously it only kills those living in the GI tract but it may also encourage migration of parasites from the GI tract to other regions unaffected by meds, which can be fatal. This is why albendazole, a much newer drug is considered superior in many cases, as its more effective for disseminated cases due to its higher absorption.