Curare is a toxic substance used in making poisonous arrowheads. It is also used as an adjunct in anesthesia at lower doses. This substance is a muscle relaxant. Physiologically, it works by blocking the motor end plate transmission. It inhibits the nicotinic acetylcholine receptor at the neuromuscular junction. It relaxes the voluntary muscles but not the involuntary muscles. It can be lethal when administered at sufficient doses. Parenteral administration of curare can cause asphyxiation and death to the target. Rudolf Boehm categorized curare into three common varieties: (1) tube curare, (2) pot curare, and (3) gourd curare.1 Gourd curare, also called calabash, is originally packed into hollow gourds, thus, the name. Its main toxic alkaloid component is curarine. Nevertheless, of the three varieties, the tube curare is commonly the most toxic among the three in terms of their LD50 values.
1Gray, TC (1947). "The Use of D-Tubocurarine Chloride in Anæsthesia". Ann R Coll Surg Engl 1 (4): 191–203. PMC 1940167.