Risks taken on travels can be infectious (turista, malaria), but can also be the consequence of decompensation of pre-existing conditions especially cardiovascular, or can be linked to ill adapted attitudes cause of hygiene risk. Prevention includes informing the traveller, vaccination, chemoprophylaxy of paludism, and dietary-hygiene advice. Advice is also necessary to prevent arthropods slings, sun aggression, jet lag, contact with animals (1 figure, 3 tableaux, 2 encadres, 4 references).