Ships' doctors were familiar even in ancient history. In the navy of the Roman Empire it was compulsory for a crew of 200 men to be led by a ship's doctor on board as a duplicary (legionary with double pay). His main task was to inspect physical aptitude of the oarsmen and to remove arrows from wounded soldiers during sea battles.

Ships' doctors were not seen particularly often on board trading ships until the Middle Ages. Fractures, contusions and dislocations arising during accidents at work were sometimes treated by the captain himself. With the great voyages of discovery, navigational medicine experienced a boom, whereby it was ultimately not academic doctors who went to sea as ships' doctors, but barbers. They were helped in their duties by the ship's cook and trained assistants.

In 1814, the Royal Navy had 14 doctors, 850 surgeons and 500 assistant surgeons, who were responsible for 130,000 men. The French "officier de santé" on board warships was a rank with basic medical training as a result of the reform of the medical system during the early Napoleonic era. In a two-class medical system the officiers de santé underwent brief and rather unspecialised training that was intended to prepare them for the standard cases of everyday medicine on land. In contrast to this, regular doctors' training covered the entire spectrum of contemporary medicine.