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!
91:1 If a person feels discomfort but he is able to go about his business like a healthy person, he may not receive any medical treatment on Shabbos, even if it doesn’t involve performing any Biblically-prohibited forms of labor. Even to anoint himself with oil – or to have it done by another, even by a non-Jew – is not allowed. (This refers to a place where oil is only used in such a manner for medicinal reasons – Rema 327:1; see later, 91:4.)
91:2 Anything that healthy people eat or drink may be eaten or drunk for medicinal purposes, even though it may be somewhat difficult and it’s obvious to others that he’s doing so for medical reasons. Anything that healthy people don’t eat or drink may not be eaten or drunk on Shabbos for its medical benefits. (One who is not at all sick may eat something that healthy people do not usually eat so long as his intention is to sate his hunger and not to improve his health – Mishnah Brurah 328:120.) One may drink sweetened fruit juice or swallow a raw egg to improve his voice. This is not considered medicinal because there’s nothing wrong with his throat. [Editor’s note: nowadays, it is not recommended to swallow raw eggs because of the risk of salmonella.]