Chiles are part of the Solanaceae, or Nightshade, family, which
includes tomatoes, eggplants and potatoes.... The quintessence
of the chile pepper, its personality, comes from the stuff that
makes it hot, chiefly and alkaloid called capsaicin (cap-SAY-a-
sin), an unusually powerful compound found in no other plant....
Capsaiconoids are produced by glands in the pepper's placenta,
which is the top of the partition just below the stem. This is
also where the seeds are attached. Since the placenta is about
16 times hotter than the meat, a pepper with its placenta, seeds
and ribs removed is substantially cooler.... the pepper scale
ranges from zero Scoville units for standard-issue bell peppers
to 5,000 or so for jalapenos and a whopping 200,000 - 300,000 for
habaneros. Pure capsaicin is 15 million.... [T]he antidote:
sugar, diary products, salt or tortillas.
-- Jim Robbins. "Care for a little Hellish Relish? Or try a
Hotsicle" Smithsonian 22 no. 10 (january 1992): 42-51.