61. Bloodletting
Deios 4:17
When a person leaves the bathhouse, he should dress and cover his head in the outer room in order to avoid catching a chill. One should be sure to do this even in the summer. After leaving the bathhouse, one should wait until he settles back down and the heat of the bath withdraws before he eats. A nap after the bath before eating is very good for a person. One should not drink cold water upon leaving the bathhouse; all the more, one should not drink while actually bathing. If a person is thirsty when leaving the bathhouse and feels he must drink, he should mix his water with wine or honey. During the winter, it is advisable to rub on oil at the bathhouse, after one has rinsed off.
Deios 4:18
One should not let blood too frequently. In fact, one should only let blood when absolutely necessary. One should not let blood in the summer or the winter, just a little in Nisan and Tishrei (roughly corresponding to April and September). A person over the age of fifty should not let blood at all. One should not let blood and go to the bathhouse on the same day. One should not depart on a journey after letting blood, nor should one let blood upon returning from a journey. One should eat less than usual on a day of when he lets blood. He should take it easy on that day, not exerting himself, exercising, or going for a walk.
Editor’s note: The Rambam lived in the 12th century and his medical advice incorporates the best knowledge of his day. Consult your rabbi with any questions involving practical application of these halachos.