Pills (Image by DodgertonSkillhause via morgueFile)
Medical research relies heavily on volunteers, although I'm aware that in some countries token amounts are paid. There are often ads run in magazines or newspapers calling for people with specific conditions to help test new treatments.
No but I have a lot of friends who have and my dad has participated in a lot of trials over the years for asthma medication. One friend are radioactive porridge for six weeks and another had her eggs collected and frozen, one trialled using chemotherapy to treat psoriasis and another was a guinea pig for a new approach to treating breast cancer. apart from the first two, all the others (including my dad) had reached a point with their condition where the doctors said they could either try the new medicine or just accept that they would die. Luckily for all of them, the new drugs were effective :)
When I was young I participated in research for a drug to relieve menstual pain. I suffered much in my youth as was happy to try anything. The drug was very successful and I relied on it for many years to come.
I would probably be a bit more cautious these days as I worry a lot more about potential side effects.