There is much discussion in halachic literature regarding the kashrut status of toothpaste and mouthwash. This is because some of the ingredients contained in these products are often derived from non-kosher sources. Although most authorities permit the use of non-kosher oral-care products, it is worthwhile to explore the halachic issues involved since it is something that is relevant to most people on a daily basis.
According to many authorities, it is forbidden to taste non-kosher food, especially liquid, even if one intends to spit it out.[1] This is due to the concern that one might accidentally swallow it. According to this approach, it is commendable to avoid using mouthwash that contains glycerin, an ingredient that is often derived from non-kosher sources. Those who wish to conduct themselves in accordance with this opinion need merely check the ingredients on the mouthwash packaging to ensure that it does not contain glycerin. A formal hechsher is not truly required.
Nevertheless, the consensus of most authorities is that it is unnecessary to insist on kosher mouthwash, or even glycerin-free mouthwash. This is because mouthwash is a product that is manufactured with the intention that it be expectorated, not ingested. As such, one need not be overly concerned that one might swallow the product.
Furthermore, there is a principle in the laws of kashrut that a product whose taste is so unappealing that even a dog wouldn’t consume it (“Eino Ra’ui L’achilat Kelev”) is not subject to any kashrut concerns.[2] Mouthwash, due to its alcohol content and other ingredients, certainly meets this requirement. While many people enjoy the minty flavor it leaves in one’s mouth, nobody would enjoy it as a drink – not even a dog.[3] According to this approach, there is no need to insist on glycerin-free mouthwash, or kosher mouthwash at all, and common custom is in accordance with this view.[4]
The halacha is similar regarding toothpaste. Most authorities permit the use of any toothpaste without the need for kosher certification.[5] Furthermore, Rav Tzvi Pesach Frank and others rule that as long as the non-kosher ingredients are a minority of the total content, they are batel, halachically insignificant and irrelevant. In the case of both toothpaste and mouthwash, the non-kosher ingredients generally make up only a small percentage of the total content and are therefore batel.[6] Rav Frank also argues that even according to those who forbid tasting non-kosher foods (as mentioned above), it refers only to foods forbidden by Torah law, not to foods forbidden by rabbinical law. Nevertheless, some authorities take a more stringent approach to all the issues mentioned above, and rule that toothpaste and mouthwash must indeed be kosher certified.[7]
Although we have seen that it is permissible to use non-kosher toothpaste and mouthwash, many authorities rule that one should conduct oneself stringently on Pesach and use only certified kosher-for-Pesach toothpaste and mouthwash. This is due to the fact that in addition to the general kashrut concerns, there may also be chametz concerns with such products.[8] Dental floss does not need to be certified kosher, either. On Pesach, however, many authorities counsel using only using unwaxed and unflavored dental floss.
[1] Rema, YD 108:5; Taz, YD 98:2.
[2] Pesachim 15b.
[3] Chut Hashani, Pesach, p.97. But see Kanei Bosem 1:25.
[4] Har Tzvi, YD 95; Or Yitzchak, YD 1:24; Divrei Chachamim p.183 note 24.
[5] Rivevot Ephraim 2:10.
[6] Har Tzvi, YD 95; Emet L'yakov, YD 103; Ibra 47.
[7] Mishne Halachot 9:154.
[8] She’arim Hametzuyanim B’halacha 11:2; Hilchos Pesach by Rabbi Shimon Eider p.27. See also Mishna Berura 442:45. Rabbi Moshe Feinstein would encourage people to only purchase kosher certified toothpaste and mouthwash, especially during Pesach.