The removal of gutta-percha and sealer from endodontically treated root canals may prompt the use of organic solvents. In the present article a number of possible solvents are described and, based upon the literature, their efficacy is assessed. Some solvents, amongst which chloroform, xylene and halothane are almost equally efficient, although all leave a debris of gutta-percha and sealer in the root canals behind. Only chloroform solves AH26 and most probably AH-plus, but very slowly. Eucalyptol and turpentine oil are slow dissolvers. Orange oil and limonene are promising. The data on other solvents, if candidates at all, are scarce. The choice of a solvent is co-determined by factors such as toxicity and sensitisation, which will be described in a second publication.