We investigated the alkaloids from the epigeal part of Thalictrum minus collected in the Kara-Kala region (Chendyr Gorge, Turkmen SSR) on June 11, 1960 during the vegetation and incipient fruit-bearing period. Chloroform extraction yielded 0.48 g of ethereal and 0.23% of chloroform fractions of combined alkaloids. The ethereal fraction was chromatographed on an alumina column, eluted with chloroform, evaporated, and the residue dissolved in methanol; gradual solvent evaporation gave prismatic crystals (mp 265-268 °C) showing a single spot on an unfixed alumina layer. The alkaloid's UV spectrum had maxima at 283 and 315 nm (log ε 3.73 and 3.41, characteristic of 1-benzyl-3,4-dihydroisoquinoline bases), IR spectrum showed absorption at 3500-3350 cm⁻¹ (hydroxyl group) and a triplet at 1630, 1605, and 1570 cm⁻¹ (conjugated -C≡N- bond). The NMR spectrum (JNM-100/100 MHz, δ-scale) showed signals of protons at 8.13 ppm (3H, N-methyl group) and 6.40, 6.23, and 6.13 ppm (9H, three methoxyl groups). These properties coincided with those of thalmethine isolated from a Bulgarian variety of Th. minus, and its IR spectrum was identical to that of thalmethine (provided by N. M. Mollov). The mass spectrum (taken on a MKh-1303 instrument, 40 eV, 130 °C, direct introduction into the ion source) showed a molecular ion peak with m/e 592 (100% intensity) and a (M - 1)⁺ peak amounting to 87% of the main peak, confirming the structure proposed for thalmethine.