Two new polyphenolic compounds, uncariagambiriine (1) and gambircatechol (2), were isolated from Uncaria gambir leaves, along with dehydrodicatechin A (3), catechin-(8 -> 6')-catechin (4), catechin-(6 -> 6')-catechin (5), and (+)-catechin (6). The structures of the new compounds, one of which is composed of an indole alkaloid and (+)-catechin, were established based on spectroscopic data.