Faced with long waiting lists, the high cost of elective treatment and fewer barriers to travel, the idea of availing healthcare in another country is gaining greater appeal to many. The objective of this review is to perform a literature review of health and medical tourism, to define health and medical tourism based on the medical literature and to estimate the size of trade in healthcare. The Medline database was used for our literature review. In our initial search for ‘health tourism’ and ‘medical tourism’ we found a paucity of formal literature as well as conceptual ambiguity in the literature. Subsequently, we reviewed the literature on ‘tourism’ in general and in the context of healthcare. On the basis of 149 papers, we then sought to conceptualize health tourism and medical tourism. Based on our definitions, we likewise sought to estimate market capacity internationally. We defined health tourism as “the organized travel outside one's local environment for the maintenance, enhancement or restoration of an individual's wellbeing in mind and body”. A subset of this is medical tourism, which is “the organized travel outside one's natural healthcare jurisdiction for the enhancement or restoration of the individual's health through medical intervention”. At the international level, health tourism is an industry sustained by 617 million individuals with an annual growth of 3.9% annually and worth US$513 billion. In conclusion, this paper underscored the issue of a severely limited formal literature that is compounded by conceptual ambiguity facing health and medical tourism scholarship. In clarifying the concepts and standardizing definitions, and providing evidence with regard to the scale of trade in healthcare, we hope to assist in furthering fundamental research tasks, including the further development of reliable and comparable data, the push and pull factors for engaging in health and medical tourism, and the impact of health tourism but, more so, medical tourism on local healthcare systems.