抄録: The potential therapeutic use of natural products as analgesics is well documented. In this context, the selectivity and specificity of animal toxins have enabled their use as potential therapeutics in the treatment of pain, making them candidates for the development of new analgesic drugs. Experimental data have indicated that spider and scorpions peptide toxins induce analgesia by selectively inhibiting ion channels involved in pain transmission and control. Amphibian skin alkaloids that are potent agonists of nicotinic acetylcholine receptor and amphibian peptide opioids have been shown to produce analgesia in humans and animals. The marine environment has proven to be a very rich source of compounds endowed with potent analgesic activity. Prialt is the first peptide derived from studies with Conus toxins, which was approved for use in humans as an analgesic and many other connotoxins are now being developed as analgesics. Also, a novel analgesic compound obtained from a Brazilian sea anemone, that exerts analgesic activity mediated by peripheral 5HT3 receptors, has been recently characterized. Snake venoms comprise a complex mixture of active substances including enzymes, non-enzymatic proteins, and peptides, which can display toxic activities. Several lines of evidence have indicated that, despite of their toxicity, various elapid and viperid venoms display central and peripheral analgesia, mediated mainly by opioidergic or cholinergic mechanisms. Recently, crotalphine, a novel - and -　opioid receptor agonist, was obtained from the venom of the South American rattlesnake Crotalus durissus terrificus. This peptide displays potent and long-lasting analgesic effect, being able to inhibit inflammatory, neuropathic and cancer pain. The pre-clinical trials with crotalphine are now in progress.