Ilustration of a plant used to make curare
Throughout time humans have relied on Nature for their basic needs for the production of food-stuffs, shelters, clothing, means of transportation, fertilizers, flavors, fragrances and medicines.

Curare is a mixture of plants from South America and is used as a paralyzing poison by South American indigenous people, especially for hunting purposes. Arrows or darts shot at the prey are dipped in curare, which leads to asphyxiation owing to the inability of the victim's respiratory muscles to contract. The curare from eastern Amazonia comes from various species of Strychnos (family Loganiaceae) plants that contain chiefly quaternary alkaloids with neuromuscular blocking action. The use of curare by Indians makes a good example of the prelude of biotechnology using venoms. Indeed, in this sense, the Indians can be considered the precursors of toxicologists in South America (LIMA et al., 2010). Based on this effect, curare started to be study by many researches. 

Amazon indian using a narrow with curare to hunt
Curare is an example of a non-depolarizing muscle relaxant that blocks the nicotinic acetylcholine receptor (nAChR), one of the two types of acetylcholine (ACh) receptors (MANALIS et al.,1977).
In the late-1930s and early 1940s, the American pharmaceutical industry launched the first modern paralyzing drugs based on indigenous South-American arrow-poisons, curare.
Distribution map of the plant in the South America

Curare never became a therapeutic drug; instead, it became a valuable tool that facilitates medical interventions, just as it facilitated animal experimentation. Its entry to modern medicine took place in the early 1940s, and its most prized application today is in surgery, where curarizing drugs complement anesthesia by imposing an utter stillness on the patient, leaving the body passive and pliant. Abdominal muscles relax and yield, and involuntary movements and contractions disappear. Classified as "surgical muscle relaxants," these modern drugs have made surgery safer by reducing the need for dangerously high levels of general anesthetics to achieve the same end (TRAUTMANN, 1982).

Preparation of the Curare used by Huaorani in the Yasuni.

Lima, M. E., Forte-Dias L., Carlini C. R. and Guimaraes J. A. Toxinology in Brazil: A big challenge for rich biodiverity. Toxicon, 1084-1091, 2010.

Manalis R. S. Voltage-dependent effect of curare at the frog neuromuscular junction. Nature, 267, 1977.

Trautmann, A. Curare can open and block ionic channels associated with cholinergic receptors. Nature, 298, 1982.