Snake venoms are recognized here as a grossly under-explored resource in pharmacological prospecting. Discoveries in snake systematics demonstrate that former taxonomic bias in research has led to the neglect of thousands of species of potential medical use. Recent discoveries reveal an unexpectedly vast degree of variation in venom composition among snakes, from different species down to litter mates. The molecular mechanisms underlying this diversity are only beginning to be understood. However, the enormous potential that this resource represents for pharmacological prospecting is clear. New high-throughput screening systems offer greatly increased speed and efficiency in identifying and extracting therapeutically useful molecules. At the same time a global biodiversity crisis is threatening the very snake populations on which hopes for new venom-derived medications depend. Biomedical researchers, pharmacologists, clinicians, herpetologists, and conservation biologists must combine their efforts if the full potential of snake venom-derived medications is to be realized.