Hot peppers are used to stimulate appetite in tropical countries, where heat slows digestion and appetite. They boost energy, promote circulation of blood and encouraging sweating.
Capsaicin, the active ingredient that produces the sensation of heat, is both an irritant and a counter-irritant. Contact with sensitive areas such as the eyes can cause stinging and inflammation, but chilli oil or chilli balm is useful in treating pain, herpes or shingles, rheumatoid arthritis or other forms of inflammation. It helps to thin blood (preventing clotting) and can protect against heart disease, as well as help an overactive or irritated bladder (when in small doses).
Green chillies can help to alleviate pain of all sorts (menstrual, headache, arthritic), but as they stimulate acid secretion in the stomach, they should be used in moderation. Another reason for caution is that chillies are generally addictive – the flushing, palpitation, clear head, sweating, salivation and improved moods mimics the kick of drug-induced pleasure which perhaps leaves you wanting to experience it again and again.