Dioscorea composita, or barbasco, is a species of yam in the family Dioscoreaceae.

It is notable for its role in the production of diosgenin, which is a precursor for the synthesis of hormones such as progesterone.

[3] Russell Marker developed the extraction and manufacture of hormones from D. mexicana at Syntex, starting the trade of D. composita in Mexico.

[6] Before becoming used industrially the tuber was used by Chinantec healers in northern Oaxaca as an abortifacient and in cures for aching joints.

It was also used by chinantecs as a poison for fishing in the Papaloapan river, and is also mentioned in use for this purpose in the Popol Vuh, the sacred book of the K'iche maya.