In the 19th century, the European beaver (Castor fiber) was headed toward extinction. The search for pain relief was one of the reasons why. Beavers were hunted for, among other things, castoreum – a smelly secretion known to have analgesic and anti-inflammatory properties. Castoreum's benefits, subsequent analysis has shown, came from salicin derived from the willow bark in the beaver's diet. For those interested in improving modalities of pain relief today, it's perhaps galling to see just how just how little the field has progressed beyond hunting beavers. In light of the huge global burden of under-treated pain, a question worth asking is where the best hope lies for developing better pain treatment modalities.