In order to study the effect of active additives in toothpastes, three different toothpastes were tested in 60 persons for a period of four weeks. The toothpastes used contained allantoin, pyridyl carbinol, alpha-tocopherol, potassium aluminum sulfate, and tartaric acid. In addition, a control paste without additives was used. In a double blind study plaque incidence of the Ramfjord teeth was determined by means of the indices of Silness and Löe and Quigley and Hein. The tissue reactions were studied by means of the S-B index and the keratinization index. After an initial examination for extablishing the origianl values, the indices were determined after 2 and 4 weeks. Statistical analysis of the data obtained allows the conclusion that none of the tested active additives in the concentrations applied had any applied had any medicamentous influence on the gingival inflammation. The therapeutical consequences are discussed.