Anisakis simplex is a parasitic worm. It infects marine mammals that feed on fish and cephalopods, its intermediary hosts. Human disease is caused by accidental ingestion of Anisakis larvae. Upon consumption of contaminated fish, cuttlefish or squid, human may develop two distinct clinical pictures: Anisakiasis is provoked by living larvae penetrating the digestive mucosa. Allergy is caused by IgE-mediate hypersensitivity to living or dead larvae in a previously sensitized individual. Anisakiasis may manifests with violent epi gastric pain, acute abdomen or eosinophilic gastroenteritis. The larvae may be visualized by endoscopy or histology. The main Anisakis allergens are not denaturated by heat or cold and resist to digestion. Allergy diagnosis relies on careful history and detection of specific IgE.