I'm trying to kick the smoking habit, but I still need my daily fix. Am I allowed to use a nicotine patch on Yom Kippur?
The Aish Rabbi Replies:
A nicotine patch, which enables the nicotine enter the blood stream directly, is not considered food or eating. Thus it is permitted to use during Yom Kippur, as long as it is applied to the body before Yom Kippur begins.
(source: "Teshuvot V'Hanhagot" by Rabbi Moshe Sternbuch 2:290)