Much evidence has been published supporting the use of mouthwashes in a number of crucial areas of oral health. These areas include antibacterial activity, home irrigation, maintenance of implant health, postsurgery uses, reduction of bacteria in dental aerosols and bacteraemia reduction. Although other commonly used mouthwashes (e.g. chlorhexidine) have been reviewed in other articles in this Supplement, this article concentrates solely on data supporting essential-oil mouthwash use in these oral health areas.