The Mayans have a word, Huuyub, meaning 'to draw breath with a puckered mouth after eating chillies'.
Chillies are members of the Solanaceae, or nightshade family of plants. Other members of this family include tomato, potato, and aubergine.
Chillies have been eaten since at least 7000 bc in South America, and at one point were used as currency.
Chillies were introduced to Europe by one Alvarez Chanca, after being mistaken for a relative of black and white pepper by Columbus.
There are many cautionary tales surrounding chillies. Nearly everyone I know has underestimated their effect at some time. Visit firegirl or another site for some poor unfortunates.
Here is a method for isolating capsaicinoids, used at your own risk. When using hot chillies always wear thick rubber gloves, and avoid all skin and eye contact. Capsaicinoids are strong irritants. 1). Puree 15 habenero peppers with 95% ethanol, until a sludge consistency is achieved. 2). Leave the mixture for 24 hours at room temperature. 3). Filter the sludge, discarding the residue. Evaporate about 90% of the ethanol, until a brick-red oil is precipitated on the surface. 4). Remove the oil with a pipette. It will be about 40% Capsaicin, and about 60% other capsaicinoids.