As you remarked, it all depends on dosage. Sure, capsaicin is toxic, if you are a newborn rat and are injected with 50 micrograms per gram bodyweight (yes, we do use the metric system in Europe) or a guinea pig. Capsaicin does destroy some nervous tissue in this case, and the animals are about 30% less sensitive to pain. I have no knowledge of permanent damage in humans due to eating capsaicin-containing stuff or due to applying capsaicin ointment to the skin. Do hardened chili-heads have any experience in this regard? Of course, anything stressful (e.g. eating habaneros or having sex, if you're not used to it) can be deleterious to persons with heart disease, so if your doctor told you to lay off it, then follow his advice - the usual disclaimer.. A. Bucsics