A common periwinkle Vinca minor L., family Apocyanaceae, serves as the source of production of drugs used primarily for the treatment of hypertonic disease. The biologically active substances of this plant are alkaloids of the indole group. At the present time, more than 20 alkaloids have been isolated from the common periwinkle and have been studied, the main alkaloid being minorine. Minorine (empirical formula C21H26N2O3) was first isolated in 1950 from the herbage of the common periwinkle in the All-Union Scientific-Research Institute of Medicinal Plants [1]. A number of methods are given in the literature for the quantitative determination of minorine in the herbage of the common periwinkle [2-10]. Neczypor's method [5] is an extraction-photometric method based on the chromatographic separation of the alkaloids in a thin layer of Kieselgel with benzene-methanol (8:2) as the mobile phase. The alkaloids are then combined with Tropaeolin 00. In view of the absence of the identical Kieselgel, it does not appear possible for the method to be reproducible, and the use of silica gel for the same purposes did not give a separation of the alkaloids. The method of Yugoslav authors [10] is based on chromatography on a thin fixed layer of silica gel of the total alkaloids of the common periwinkle with subsequent spectrophotometry at 280 nm. This method also could not be reproduced because of the absence of information on the mobile solvent phase. In view of this, we have developed a method for the quantitative determination of minorine in the herbage of the common periwinkle which is based on the extraction of the total alkaloids by dichloroethane and its chromatographic separation followed by the colorimetric determination of minorine tropaeolate.