Fenbendazole is an effective treatment for eliminating a variety of parasites in your dog's/cat's system. Fenbendazole eliminates intestinal parasites including roundworms (Toxocara Canis, Toxascaris leonina), hookworms (Ancylostoma caninum, Uncinaria stenocephala), some tapeworms (Taenia pisiformis), whipworms (Trichuris vulpis) and giardia.