Chilli anaesthetic
Some hot news in from New Scientist..
Clifford Woolf and his colleagues at Harvard Medical School have now discovered a way of blocking just the pain neurons using capsaicin - the active ingredient in chilli peppers - along with a version of lignocaine that can’t diffuse through cell membranes unassisted. [....] Woolf’s team is testing other chemicals that can activate the TRPV1 receptor, since people may not like the initial pain of a dose of chilli pepper. Tests on volunteers are expected within two years.
I can think of a couple of people who might want to volunteer for testing.. 
