Worrying about health and diseases is a mostly circumstantial, moderate and transient concern. But, health worries can heat up to become excessive, persistent and pathological, despite some attempts to cope with it (reassurance seeking, bodily checking, avoidance of illness situations). Between ordinary health concerns and hypochondriasis, clinical slight differences should be identified. Although they are not described in international classifications, they cause psychological distress and/or health-related risk-taking. Still little known and used in France, the concept of health anxiety emphasizes this clinical diversity. This literature review aims to specify this concept in describing the nature of cognitive and behavioral factors that initiate, reinforce and perpetuate anxiogenic process, but also emphasizes the clinical relevance of the concept of health anxiety.