Capsaicin is good for you, and if used properly, certainly enhances the taste of most foods.
However, i hear that too much capsaicin has been linked to stomach cancer. Also, it increases acid production in the stomach - good news if you're hypo-acidic, bad news if you're hyper-acidic.
For some reason, part of my digestive tract reacts very badly when it comes into contact with chilli. Had this problem for years, and just taught myself to handle it, since i didn't want to stop using chillies in my food (its kinda hard to do in an indian family). However, over the past few months i've developed another problem, specifically stomach discomfort, symptoms of which point to an ulcer (but i'm too much of a wuss, to go and check it out). Anyway, I finally decided to totally cut chilli, and anything particularly hot, out of my diet. And i've experienced quite a bit of improvement
Hmmmm...seems i've turned the stereotype of the chilli-munching indian on it head
"The good Christian should beware the mathematician and all those who make empty prophecies. The danger already exists that the mathematicians have made a covenant with the devil to darken the spirit and to confine man in the bonds of hell." - St. Augustine