A large part of the population suffers from halitosis. Causes can be both oral and non-oral changes. Coating of the tongue as well as marginal periodontitis are the most frequent oral causes. Non-oral causes are primarily tonsillitis and sinusitis but also general diseases as well as special diet habits. Non-real halitosis or halitophobia is unterstood by the compulsive idea to suffer from bad breath and to irritate others by this. This compulsive idea can change the complete pattern of behavior of these patients which in itself can lead to self-isolation and even to suicide. Consultation hours for halitosis should be prepared for patients with non-real halitosis and build up corresponding interdisciplinary contacts.