The plant Solanum tuberosum has been studied previously [1-4], but the top shoots, roots, and the skin of the tubers of a local potato in the period of complete ripeness of tubers have not been investigated chemically. The comminuted air-dry raw material was extracted with 5% acetic acid by the method of Kuhn and Low [5], alkaloids were precipitated with 25% ammonia, the dried precipitate was treated with methanol, and the concentrated methanolic solution was passed through a silica gel column and eluted with methanol. The mixture of alkaloids from various plant parts mainly consisted of three substances (Rf 0.08, 0.35, 0.56). From the top shoots, three bases (I, II, III) were isolated via ethanol treatment and column chromatography. Their IR spectra contained absorption bands of hydroxy group (3420 cm⁻¹), double bond (1650 cm⁻¹), and glycoalkaloid characteristic bands (1000-1150 cm⁻¹); mass spectra had strong peaks of ions with m/e 150 (100%), 204, and 397 (main fragments of solanidine). Hydrolysis of I, II, and III yielded an aglycone identical to solanidine, and neutral fractions showed galactose, glucose, rhamnose (I); glucose (II); glucose, rhamnose (III) via TLC. Their physicochemical constants coincided with α-solanine (I), α-chaconine (II), and β-chaconine (III) respectively. Table 1 gives the content of alkaloids in different organs and gathering times of early and late varieties.