This document discusses natural products that can serve as leads for new pharmaceuticals, focusing on curare alkaloids as neuromuscular blocking drugs. It provides background on curare used by South American Indians as arrow poison and the isolation of tubocurarine as the active component. The document describes the mechanism of action and classification of neuromuscular blocking drugs as non-depolarizing or depolarizing. It discusses synthetic analogues of tubocurarine such as pancuronium, vecuronium, and atracurium as well as the depolarizing drug succinylcholine.