Does one need a heksher for mouth wash. It isn’t made to drink, and the fact that it is made with alchohol I am careful not to swallow. I have heard that some mouthwashes have geletine in them and this is the worry. I have checked the ingredients on various brands and find no mention of geletine.
It is true that mouthwash is not made for drinking purposes, and it is moreover inedible, and made to rinse and to expell (spit out), and not for swallowing. For this reason, some rule that it does not require a hechsher.
However, because it has a good taste, and it is sometimes swallowed in small amounts, many are particular to have a hechsher on mouthwash. This is based on the ruling of the Taz (Yoreh De’ah 98:2) and others, who write that one must not taste non-kosher foods, even if they are not swallowed.
Mouthwash usually contains glycerin, which is a (sometimes) non-kosher ingredient that gives the mouthwash a refreshing sensation.
Because nowadays there are many kosher mouthwashes, one should be careful to use them. If kosher mouthwash is not available, there is room to be lenient, taking care not to swallow the mouthwash (this is the ruling of Rav Scheinberg, and others).