Chapter 91:9 & 10a
Non-Critical Illness on Shabbos
9. A person who is uncomfortable because he overate, may place his finger
down his throat on Shabbos, so that he will vomit (1).
10 (a). [The following applies to] a wound that is not critical (2): one
may not place a medicated dressing upon it on Shabbos, even if it was
prepared from the day before, nor may one place anything on it that serves
as a remedy ("refuah"); this includes a leaf (that is known for its
medicinal properties), or an old, dry piece of cloth (3), for it too aids
in the healing process (4).
However, one may, on Shabbos, place something upon it which will prevent it
from being scratched (or irritated).
(1) Using a drug to induce vomiting would be prohibited due to the
rabbinical prohibition against taking medicine on Shabbos.
(2) This applies to a wound that is neither life-threatening, nor does it
cause severe pain, or threaten the normal functioning of a limb. In any of
these cases, the prohibition against applying a medical remedy on Shabbos
would obviously not apply.
(3) The Talmud implies that old, dry cloth (that has never been used before
on a wound), somehow aids in the healing process. Since the Talmud was
written about 1500 years ago, its medical advice should not be relied upon
without consulting a qualified physician.
(4) Of course, one can and must do whatever is necessary to prevent
infection or other deterioration of the wound.