262, see text[1] Cynanchum is a genus of about 300 species including some swallowworts, belonging to the family Apocynaceae.

The taxon name comes from Greek kynos (meaning "dog") and anchein ("to choke"), hence the common name for several species is dog-strangling vine.

Like other species of the milkweed family, these plants bear follicles, which are podlike dry fruits.

The root of Cynanchum atratum is used in Chinese traditional medicine and called Bai wei.

Revision of the genus taxonomy in 2023 identified two new synonyms: Vincetoxicum sibiricum f. linearifolium, described from Shandong, China in 1877, but long neglected and Cynanchum gobicum, previously believed to be endemic to Mongolia.