Fenbendazole and Mebendazole are both benzimidazole antiparasitics with identical mechanisms — but they differ fundamentally in their regulatory status. Mebendazole is FDA-approved for human use with 50 years of clinical data. Fenbendazole is primarily a veterinary medicine not FDA-approved for humans. This complete comparison covers approved uses, dosage protocols, safety profiles, and which to choose for your situation.