Hookworm is a parasitic roundworm — Ancylostoma duodenale and Necator americanus — that lives in the human small intestine, anchoring to the gut wall and feeding on blood. Infection comes from walking barefoot on contaminated soil: larvae penetrate the skin, travel through the lungs, are coughed up and swallowed, and mature in the gut. A heavy worm burden drains blood relentlessly, causing iron-deficiency anaemia, protein malnutrition, and stunted growth in children — a major, neglected burden across the rural tropics. Treatment is simple (albendazole or mebendazole) and prevention is sanitation: latrines, shoes, and clean soil. Hookworm reminds us that nutrition is not only about food eaten, but about what parasites steal.