The majority of mouthwashes contain some sort flavoring. Peppermint or spearmint flavors are the ones used very often and they are known for their ability to naturally repel mosquitoes and insects. Insects don't like the smell of these aromas, so when you use them, you will be less likely to get bitten by a bug. These mouthwashes contain alcohol as a preservative, which can cause a burning sensation if used on damaged skin. Keep that in mind if using any of these products as a repellent on your skin or on a skin of your horse companion.