From the combined alkaloids of the leaf blades of Carica papaya L. introduced into the Gagra out-station of the Main Botanical Garden of the Academy of Sciences of the USSR we have previously isolated and identified the alkaloid carpaine. By preparative TLC in a fixed layer of LS 5/40 silica gel in the ethanol--acetic acid-water (52:25:25) system we have now isolated a crystalline base. After two recrystallizations no additional spots, either of alkaloids or of other substances of basic nature, appeared on PC or on one- and two-dimensional TLC chromatography. The base isolated had mp 66-68°C, [α]ₙᵒ + 4.95°C (c 1.0; ethanol). Its IR and NMR spectra were identical with those of pseudocarpaine. A comparison of the results obtained with those given in the literature permitted the base isolated to be considered as pseudocarpaine.