"Six men remain in intensive care after being taken ill during a clinical drugs trial in north-west London. "

http://news.bbc.co.uk/1/hi/england/london/4807042.stm

This is pretty vicious and they were suggesting on the Today programme that they thought people would be less inclined to come forward for such tests.

I can't see that happening myself. Surely you only do it if you need the money as everyone recognises you could suffer a horribly vicious death, with blackened, puss-ridden blood squirting from every orifice.*

*note: this did not happen to the guys in the news story.