Curare is a plant-derived substance traditionally used by indigenous peoples in South America as a poison for hunting. It is made from various plants, including those from the Chondrodendron and Strychnos genera. When introduced into the bloodstream, curare acts as a neuromuscular blocker, causing paralysis by inhibiting nerve signals to muscles. In modern medicine, curare and its derivatives are used in controlled settings as muscle relaxants during surgeries. These substances help facilitate intubation and improve surgical conditions by relaxing the muscles. However, they must be administered carefully due to their potent effects on the respiratory system.