Judgments pervade any assessment of risk, including the definition of outcomes that matter, the breadth of the effects to be considered, and measures of consequences. In risk perception, travellers may confound the likelihood and severity of outcomes, and also tend to be influenced by attributes of the hazard apart from its actual consequences. Familiarity, visibility, and controllability of a hazard all influence the perception of risk. Understanding of the perceptions as well as the reality of risk in travel can help travel health advisers to better prepare travellers for safer and healthier travel.