General Plant Info
Acacia confusa is a perennial tree native to South-East Asia and containing high concentrations of psychoactive tryptamines in its root bark. It appears attractive for use in ayahuasca analogs, though at this point, experience with such preparations remains limited. Some local names include Acacia Petit Feuille, Small Philippine Acacia, Formosa Acacia (Taiwan Acacia) and Formosan Koa. The tree has become very common in many tropical Pacific areas, including Hawaii, where the species is considered invasive.
- N-methyltryptamine, 1.43%
- N,N-dimethyltryptamine|N,N-dimethyltryptamine, 1.15% (Liu et al 1977 ref. Trout's Notes)
- N-methyltryptamine, 0.04%
- N,N-dimethyltryptamine, 0.01% (Arthur et al 1967 ref. Trout's notes)
No alkaloids are found in the phyllodes (leaf-like structures).
- Neurolathryogen, i.e. α-amino-β-oxalylaminopropionic acid, which can cause neurological damage, paralysis and death.
The seeds are considered poisonous and reported to cause headache upon ingestion. 
Ayahuasca analogs prepared with Acacia confusa root bark are known as Formosahuasca (after Formosa acacia, i.e., the beautiful acacia, presumably after Ilha Formosa, i.e., the beautiful island, the original Portuguese name for Taiwan), or alternatively as Chinahuasca or Asian Ayahuasca.
The psychoactive tryptamines extracted from Acacia confusa are described in a number of publications. 
The plant is considered medicinal in Taiwan. (The same publication reports it as toxic, without providing further details.)
Online excerpts from Chinese medicine books (precise references are not given) state that the root can be used for detoxification, treating larynx and windpipe inflammation and liver disorders. (Original Chinese text: 根有清热解毒、解暑发表的功能。可用于治疗咽喉肿痛，黄疸性肝炎及慢性气管炎等。)
Positive outcome has been reported for applications of Acacia confusa bark extract to combat the liver toxicity of carbon tetrachloride in rats.  Goat foraging on the plant has been observed. 
1) The tree is very common in Taiwan, where its local name is 相思樹 (which amusingly translates as "thinking-of-each-other tree").
2) The root (相思樹根) has some limited use in traditional medicine, externally and perhaps internally for liver disease.
3) The root does not seem to be carried by Chinese medicine stores (中藥店), but it is carried by "herbal medicine stores" (草藥店 or 青草店), though not every store would have it, since the demand is low.
4) There is a huge conglomeration of these herbal shops next to Longshan temple (龍山寺) in Taipei, where fresh root can be purchased (as of April 2010, 150 Taiwan dollars, roughly $5, for 600g, with 1 day pre-order needed). The bark can be easily separated from the fresh root.
- Acacia confusa on Wikipedia
- Photographs of the different parts of the plant
- Erowid Acacia vault
- A group in Taiwan conducting ayahuasca sessions using Acacia confusa
- Acacia confusa at psychoactiveherbs.com
- Reality Sandwich
- Seemingly promising Acacia species lacking bioassay reports in Ayahuasca: alkaloids, plants & analogs by Keeper of the Trout
- Pacific Island Ecosystems at Risk (PIER)
- Erowid Report
- A Guide to Brewing Asian Ayahuasca
- Erowid Report
- Acacia confusa and Formosahuasca at the DMT-Nexus forum
- Arthur, H.R., Loo, S.N. & Lamberton, J.A. Nb-methylated tryptamines and other constituents of Acacia confusa Merr. of Hong Kong. Aust. J Chem. 20 (1967) 811 online text; Lee, T.H. and Chou, C.H. Flavonoid aglycones and indole alkaloids from the roots of Acacia confusa, Journal of the Chinese Chemical Society 47 (2000) 1287-1290, online text; Buchanan MS, Carroll AR, Pass D, Quinn RJ. NMR spectral assignments of a new chlorotryptamine alkaloid and its analogues from Acacia confusa, Magn Reson Chem. 2007 Apr; 45(4):359-61, online text
- Li, Thomas S. C. Taiwanese Native Medicinal Plants: Phytopharmacology and Therapeutic Values, CRC Press (2006), ISBN: 0849392497, p.2. online GoogleBooks preview full text
- Tung, Y.-T., Wu, J.-H., Huang, C.-C., Peng, H.-C., Chen, Y.-L., Yang, S.-C., Chang, S. T. Protective effect of Acacia confusa bark extract and its active compound gallic acid against carbon tetrachloride-induced chronic liver injury in rats, Food and Chemical Toxicology 47 (2009) 1385–1392, online text
- K. Hagstrom, M. L. Christiansen and E. R. Cleveland. Plants in Hawaii that are eaten by goats, J. Haw. Pac. Agri. 4 (1993) 101-105, online text