Here we report the cytotoxic activity of three known compounds isolated for the first time from Corydalis pallida (Papaveraceae). An isoquinoline alkaloid, berberine, exhibited cytototoxic activity against two human cancer cell lines, HT-1080 (human fibrosarcoma) and SNU-638 (human stomach adenocarcinoma), with IC50 values of 3.2 and 3.4 microg/mL, respectively. N-trans-feruloyltyramine and N-trans-feruloylmethoxytyramine were also isolated from this plant but were inactive.