Curare

Chondrodendron tomentosum, the main source of 'tube curare' and principal source of D-tubocurarine (DTC), the alkaloid constituting medicinal curare
Strychnos toxifera, the Strychnos species which is the principal source of 'calabash curare' and its main active constituent, the alkaloid toxiferine

Curare (/kʊˈrɑːri/ or /kjʊˈrɑːri/; kuu-RAH-ree or kyuu-RAH-ree) is a common name for various alkaloid arrow poisons originating from plant extracts. Used as a paralyzing agent by indigenous peoples in Central and South America for hunting and for therapeutic purposes, curare only becomes active when it contaminates a wound or is introduced directly to the bloodstream; it is not active when ingested orally.

Curare is prepared by boiling the bark of one of the dozens of plant sources, leaving a dark, heavy paste that can be applied to arrow or dart heads.

These poisons cause weakness of the skeletal muscles and, when administered in a sufficient dose, eventual death by asphyxiation due to paralysis of the diaphragm. In medicine, curare has been used as a treatment for tetanus and strychnine poisoning and as a paralyzing agent for surgical procedures.