Recently in holistic dentistry, more statements are spread that non-vital teeth and root canal treated teeth release mercaptans and thioethers. These products are expected to cause a postulated direct toxic effect as well as pathological immune reactions. In reference to a study by Jacobi-Gresser et al., it is stated that the laboratory results can be impacted significantly by retreatment of a root canal treatment or a tooth extraction. It is therefore suggested that at allegedly increased laboratory values an extraction of a tooth with a non-vital pulp or that has already been root canal treated is indicated. Mercaptans are aromatic or ali¬phatic thioalcohols, give off a very unpleasant odor and result from degradation and the decomposition process of organic material. They naturally act as flavoring substances in milk, cheese, onion, garlic, coffee aroma and nuts. Methanthiole (methyl mercaptan) forms during bacterial protein degradation, amongst others also in human saliva. It is the main cause of halitosis, however, it also exists physiologically in the blood, brain and other human organs. Mercaptans are produced daily during the anaerobic metabolization of intestinal proteins. Increased methyl mercaptan-values in air were found in decompensated liver cirrhosis, and in patients with periodontal diseases or gastric ulcers and tumors. Thioethers are sulfur analogues of ethers, mostly insoluble in water and have an extremely unpleasant odor. The dimethyl sulfide results from the decomposition of sulfurous proteins, but is also responsible for the odor and taste of different types of truffles.