5-htp (5-hydroxy-tryptophan) is an amino acid that your body converts directly into the neurotransmitter seratonin. It was a health craze in the US awhile back as I remember, and many people still find it makes a better antidepressant than St. John's Wort or SSRIs like Prozac (both of which should NEVER be used together with 5htp!).
In any case, I'm sold on it. I take 100mg of 5htp every day, and have never felt better. Screw prozac and its ilk.
In the US, you can buy 5htp at any pharmacy or health food store, for a reasonable price. But I've talked to many a Taiwense pharmacist, and I've found the only place where I've had any luck is Zhongli Pharmacy (1F No. 13-5 Xiangyang Rd. Taipei City). This is the giant place across the street from the Er Er Ba Peace Park, in the neighborhood of Taipei Main Station. They need to special order it through China Petrochemicals, and it costs NT$1800 for 50 100mg capsules. (ouch!)
It seems that 5htp's legal status is Taiwan is a lot like in Australia -- not approved by the Ministry of Health for sale to the public, but not explicitly banned either. It boggles my mind why this wonder chemical has trouble getting approved by a lot of governments. I have a sneaking suspicion it's because this chemical is widely known and used by recreational ecstasy users, because it ameliorates the unpleasant side effects of this drug. By making 5htp not widely available, do governments hope to curb ecstasy use? Sounds a lot like a handing - out - condoms - in - schools type problem.