The third edition of the International Medical Guide for Ships shows designated first-aid providers how to diagnose, treat, and prevent the health problems of seafarers on board ship. Since its first publication in 1967, the International Medical Guide for Ships has been a standard reference for medical care on board ships. The second edition, written in 1988, was translated into more than 30 languages, and has been used in tens of thousands of ships. This, the third edition, contains fully updated recommendations aimed to promote and protect the health of seafarers, and is consistent with the latest revisions of both the WHO Model List of Essential Medicines and the International Health Regulations. The International Labour Organization's Maritime Labour Convention 2006 stipulates that all ships shall carry a medicine chest, medical equipment and a medical guide. The International Medical Guide for Ships supports a main principal of that convention; to ensure that seafarers are given health protection and medical care as comparable as possible to that which is generally available to workers ashore. By carrying this guide on board ships, and following its instructions, countries can both fulfill their obligations under the terms of the Maritime Labour Convention 2006, and ensure the best possible health outcomes for their seafaring population.