To keep healthy requires several things. People should develop sound habits in terms of eating, drinking, exercise, sleep, posture, sexual intercourse, and bathing. Physicians must pay special attention to age and seasons, and modify the lifestyle accordingly. Certain parts of the body need special attention, such as eyes, ears, hands, feet and so on. One ought to be particularly careful in case of epidemic diseases and take appropriate protective measures. Then there is the environment, which should be as healthy as possible; here one has to pay particular attention to the ambient air, the water one drinks, and the location where one lives. Finally, there are many psychic factors that affect one’s health...
Left: A physician with a patient about to vomit. Taken from a 13th-century copy of the Arabic version of Dioscorides’ On Medicinal Substances.