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!
91:17 The bedridden person may eat and drink medications and carry out medical treatments, whether this means doing them himself or others doing them for him, so long as no activities prohibited on Shabbos are required, not even Rabbinic prohibitions. However, if something requires that even a Rabbinically-prohibited activity be performed, it may be done by a non-Jew. If a non-Jew isn't available, a Jew may perform a Rabbinically-prohibited activity if he does so in an unusual manner.
91:18 If a non-Jewish doctor is preparing vaccinations for children, if the Jew can pay him to give the shot after Shabbos, he should do so. If not, and if it must be done on Shabbos, then the Jew should not hold the child receiving the shot; it would be better for a non-Jew to hold him.