Most mouthwashes can be used in the Philips Sonicare AirFloss. However, mouthwashes containing Isopropyl Myristate and other essential oils should not be used in the AirFloss as they can harm the plastics in the device. Also, do not use concentrated mouthwashes in your Philips Sonicare AirFloss. These mouthwashes are identifiable by their glass or ceramic bottles or containers. Use of concentrated mouthwashes or mouth rinses in the AirFloss can damage the plastics.