Question: May one take Tylenol or sleeping pills on Shabbat? Also, may Tylenol be administered to an infant who is running a fever on Shabbat?
Answer: In the previous Halachot we have explained that an individual who is not truly ill (i.e. lying down in bed) may not take medication on Shabbat. We have likewise explained the reason behind this enactment.
The Sefer Eshel Avraham (Chapter 327) writes that one may wash one’s head with an alcoholic beverage on Shabbat in order to be able to fall asleep easily. This is not similar to other forms of healing which are forbidden on Shabbat, for causing one to fall asleep is not considered healing.
Based on this, Hagaon Harav Shlomo Zalman Auerbach zt”l writes (in his Shulchan Shlomo, Chapter 328) that one may take sleeping pills on Shabbat. Although other luminaries of our generation disagree, Maran Rabbeinu Ovadia Yosef zt”l rules that one who requires sleeping pills in order to fall asleep may use them on Shabbat, for this is not considered healing an illness since the lack of sleep is not actually an illness and is only extremely uncomfortable. The edict of our Sages therefore does not apply here. He proceeds to list several other reasons for leniency in this case (see Chazon Ovadia-Shabbat, Part 3, page 367).
Pain Relievers and Fever Reducers
Regarding taking Tylenol and the like, we have already explained that if one is so ill that one must lie in bed as a result of his pain or discomfort, one may take medication as needed, for the enactment against “crushing herbs” which prohibits taking medicine on Shabbat does not apply to one who is truly ill. Thus, although one may not act leniently and take Tylenol to relieve the minor discomfort of a light headache and the like, if one is truly ill and suffers from fever and major aches and pains, one may take such medications in order to relieve the pain and reduce the fever (Chazon Ovadia-Shabbat, Volume 3, page 368).
The Law Regarding an Infant
There is room for leniency regarding an infant in any case, for we have written that one may administer any medication necessary to a child under nine years of age. This is especially true with regards to infants since an increase in body-temperature poses a danger to them and one must therefore quickly balance their body-temperature.
Summary: If necessary, one may take sleeping pills on Shabbat. If one suffers from a slight discomfort, such a small stomach ache and the like, one should not take medication to alleviate the pain. However, if one’s entire body is in pain, for instance, if one must lie down in bed as a result of his pain or illness, one may take any medication necessary. It is permissible to administer any medication necessary to an infant on Shabbat in any case.