The Kitzur Shulchan Aruch was written in the 1800s, based on the Shulchan Aruch, which was written in the 1500s. This chapter discusses the medical treatments of the times, some of which may now be discredited. Here, we only address the permissibility of those treatments on Shabbos, not their medical effectiveness. Please consult your own rabbi regarding matters of medical treatment on Shabbos. In case of serious illness or injury, seek medical attention!
91:9 If a person is in discomfort from overeating, he is allowed to put his finger down his throat in order to make himself vomit (but he may not use an emetic on Shabbos – OC 328:39). [Editor’s note: Self-induced vomiting should not be used as a form of weight loss (and is prohibited even on weekdays – see OC, ibid.). If someone has ingested something poisonous, contact poison control for the appropriate course of action.]
91:10 If a wound is not dangerous, one may not put a bandage on it, even if it was prepared before Shabbos. He may not put anything on it as a form of medical treatment, not even a leaf or a dry piece of old cloth that can help healing. He may, however, put something on it to keep from scratching it. If there was a bandage on the wound from before Shabbos, he may open one end to clean the wound, and then the other end. He may not clean the bandage itself since this constitutes smearing (memareiach), which is prohibited on Shabbos. If the bandage fell off the wound and onto the floor, he may not put it back on but if it fell onto some object, he may replace it. (If one intentionally removed the bandage, there is a difference of opinion as to whether it may be replaced. Mishnah Brurah 328:82 feels that one may be lenient in a case where the bandage was removed to fix it.) If he is very distressed about it, he may direct a non-Jew to replace it but one may not ask a non-Jew to prepare a bandage on Shabbos because doing so involves Biblically-prohibited activities and is therefore not permitted to be performed through a non-Jew unless one is seriously ill. [Editor's note: All of this refers to dressing a wound with a traditional cloth bandage; our small adhesive bandages are not generally considered problematic on Shabbos, though one may not smear them with ointment on Shabbos.]