Question:
Are caffeine suppositories permissible on Yom Kippur?
Thank you
Answer:
Although one is allowed to use caffeine suppositories on erev Yom Kippur to make the fast easier, on Yom Kippur one should refrain from using them unless the fast causes excessive suffering or there is a possibility that the fast will be broken.
Sources:
Teshuvas Chelkas Yaakov 2:58, Tzitz Eliezer 7:32, Kinyan Torah 4:68.
