Mebendazole (CAS No.: 31431-39-7) is a classic broad-spectrum benzimidazole anthelmintic with dual applications in human clinical medicine and veterinary practice. It is a first-line anti-helminth drug recommended by the World Health Organization (WHO) for human intestinal worm infections, and a widely used dewormer for livestock, poultry and companion animals due to its high efficacy, low systemic toxicity, and convenient oral administration. Its core mechanism of action is selectively inhibiting the synthesis and polymerization of β-tubulin—a key structural protein of microtubules in helminth (worm) somatic, reproductive and intestinal cells. This inhibition disrupts the formation of microtubule networks, impairs the helminth’s nutrient absorption (via intestinal microvilli), cellular division, muscular motility and egg production, ultimately leading to worm starvation, paralysis and death. Mebendazole acts potently on the adult and larval stages of most intestinal helminths, and also exerts an ovicidal effect (inhibits egg hatching and maturation), which is critical for preventing the spread of helminth infections. Notably, it has extremely low oral bioavailability in humans (~5%) and most mammals, meaning it acts primarily locally in the gastrointestinal tract with minimal systemic absorption—this is the main reason for its low side effect profile and high safety for all age groups.
Mebendazole’s clinical value lies in its broad anti-helminth spectrum and excellent safety, making it the gold standard for treating intestinal helminthiasis in humans (especially children) and a reliable dewormer for veterinary use. Its detailed uses in human medicine and veterinary practice are systematically elaborated below, in line with WHO clinical guidelines and international veterinary pharmacopoeia standards.
1. Core Uses: Human Clinical Medicine (First-Line Indication)
Mebendazole is the first-choice oral anthelmintic for the treatment and control of intestinal helminth infections in humans of all ages (including infants ≥1 year old, children, adults and the elderly). It is the most commonly used drug for single and mixed intestinal helminth infections globally, and is a key drug in WHO’s global deworming programs for school-age children in endemic areas. It targets nearly all major human intestinal nematodes and some cestodes (tapeworms), with high cure rates (85%–100%) for most common infections.
1.1 Treatment of Intestinal Nematode Infections (Primary Human Indication)
Intestinal nematodiasis is the most prevalent human parasitic disease worldwide, and mebendazole is the first-line treatment for the four major species causing human infections:
Ascaris lumbricoides (human roundworm): The most common human helminth infection globally. Mebendazole rapidly clears adult roundworms from the small intestine, relieving symptoms such as abdominal pain, bloating, anorexia, and stunted growth in children; it also kills larval stages migrating in the body and inhibits egg production, preventing reinfection and transmission. A single or short-course regimen is sufficient for a high cure rate.
Enterobius vermicularis (pinworm): A highly contagious helminth infection, especially common in preschool and school-age children. Mebendazole is the first-choice drug for pinworm infection, with an ovicidal effect that is far superior to other anthelmintics—this is critical because pinworm eggs are the main source of transmission (via hand-mouth contact). A single dose is typically administered, with a repeat dose 2 weeks later to eliminate newly hatched larvae, achieving a nearly 100% cure rate and stopping household/herd transmission.
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