You can use a generic mouthwash in your WaterJet Flosser. We recommend using no more than a 1:1 ratio of mouthwash to water. Do not use iodine, bleach, tea tree oil, salt, baking soda, or water insoluble concentrated essential oils in this product. Use of these can reduce product performance and shorten the life of the product. If additives are added to the water in the reservoir, rinse the system with a reservoir full of clean water after each use. Failure to rinse the unit may result in loss of product performance and/or function. Growth of bacteria and/or molds could also be enhanced