The Rule of Health (Regimen sanitatis) is a didactic medieval poem in hexameter verse containing a popular simplification of the Galenic rules on diet and hygiene in the context of domestic medical practice. Composed around the twelfth century, it gradually became a very popular work memorized by generations of doctors and translated into several vernacular languages. The fact that it often circulated under the title, The Salernitan Rule of Health (Regimen sanitatis Salernitatum) suggests that it was authored by one of the physicians working in the famous medical school of Salerno. As shown in this printed edition, it was edited (with commentary) by the Spanish physician Arnau de Vilanova (ca. 1240–ca. 1311).