Abstract: The present study was designed to determine the chemical constituents of the stem tuber of Pinellia pedatisecta. The chemical constituents were isolated and purified by various chromatographic techniques, and their structures were elucidated on the basis of physicochemical properties and spectral data. Three new alkaloids (compounds 1 , 2 , and 3 ) were obtained and identified as 9-((5-methoxypyridin-2-yl)methyl)-9H-purin-6-amine ( 1 ), 4-(2-(2, 5-dioxopyrrolidin-1-yl)ethyl)phenyl acetate ( 2 ), and N-(9-((5-methoxypyridin-2-yl)methyl)-9H-purin-6-yl)acetamide ( 3 ). These compounds were evaluated for their cytotoxicity against human cervical cancer HeLa cells. Compounds 1 and 3 significantly inhibited the proliferation of HeLa cells with IC₅₀ values being 3.02 ±0.54 and 7.16 ±0.62 μmol·L^-1, respectively.