﻿AbstractCynanchumthesioides, a species widely distributed in north-eastern Asia, is revised to include two new synonyms:Vincetoxicumsibiricumf.linearifolium, described from Shandong, China in 1877, but long neglected andCynanchumgobicum, previously believed to be endemic to Mongolia. Typification forC.thesioidesand all its synonyms is given, including lectotypification ofV.sibiricumvar.australeandV.sibiricumf.linearifolium. An updated description, three figures showing the diverse habitats, habits and variation in morphological characters, and a general distribution map are also provided.