Halitosis is a very common condition which may affect up to 30% of the population. In most cases the aetiology of the condition is from local oral causes (oral malodour). Oral malodour is the result of the action of anaerobic bacteria in producing a range of malodorous molecular species including volatile sulphur compounds. Whilst malodour is often associated with the presence of periodontitis, in many cases there is no such link, and the evidence points to the importance of these anaerobic bacteria in tongue coatings which results in the clinical presentation of oral malodour. Management of oral malodour is directed at managing and reducing the bacterial load both in periodontitis and in tongue coatings by instituting proper oral hygiene measures, control of tongue flora by brushing or scraping, and possibly the adjunctive use of antiseptic agents. Treatments have also been proposed to neutralise malodorous compounds by chemical agents to mask the presence of the condition. Further evidence is required to demonstrate the long-term efficacy of therapies for this troublesome condition.