A new flavone C-glycoside, 5-O-acetyl-2"-alpha-rhamnopyranosylisovitexin (1), was isolated from the aerial parts of Lychnis senno Siebold et Zucc. (Family Caryophyllaceae), along with 2"-alpha-rhamnopyranosylisovitexin (2), 2"-a-rhamnopyranosylisoorientin (3) and isoorientin 3'-mehyl ether (4). All