Q. Can someone suffering from severe dry mouth, just take some water on Tzom Gedalia place it in his mouth, swivel it and then just spit it out?

A. Oruch Hashulchan (O.H. 567: 3) permits washing one’s mouth in the minor days of Taanis, if he does so while ones head is bending down and with a small amount of water. Mishna Berura (567: 11) permits in cases of great pain even on Tisha Beav. (see also Minchas Yitzchok 4: 109).

Horav Shlomo Miller’s Shlit’a opinion is similar.

Rabbi A. Bartfeld as revised by, Horav Dovid Pam, Horav Aharon Miller, Horav Chanoch Ehrentreu and Horav Kalman Ochs Shlit’a