Travel medicine deals with travellers' diseases. The target group is therefore distinct from tropical medicine. It has gained in significance due to the increase in tourism and professional work abroad in the last 50 years. Dangerous and widespread diseases in tropical countries, in particular tropical malaria, have come into focus in industrialized countries because of their appearance in travellers. Travel medicine deals not only with infectious or transmittable diseases, but also with the ability of patients with chronic diseases to travel, the medical aspects of flying, as well as the health hazards of professional work or high-risk sports abroad. The risk of disease as a result of travelling can be minimized by advice and prophylactic measures, such as vaccinations and drug prophylaxis against malaria, if indicated. On return, medical symptoms should be investigated promptly to ensure early detection of life-threatening disease courses, particularly tropical malaria, as well as to prevent the occurrence of small-scale epidemics. A small number of diseases can also emerge after several years, such as benign types of malaria, amoebic liver abscess and visceral leishmaniasis (kala-azar). Aids also belongs to these diseases. Therefore, in this era of HIV pandemic travellers concerned should be made aware of the risks.