So-called AYAHUASCA TEA (a decoction of the bark and leaves of Psychotria viridis, Rubiaceae and/or Banisteriopsis caapi, Malpighiaceae), frequently used in traditional Brazilian medicine as an ANTIDEPRESSANT, was subjected to the "forced swimming" test and the "open field" test. The forced swimming test is an internationally recognized pharmacological model for testing of substances and extracts with antidepressant effects. Both experimental tests revealed an antidepressant effect, whereby interestingly enough the lowest concentrations (2.5 mg/kg animal body weight) were the most effective dosages. The decoction tested contained 10.6% extracted substances, including the alkaloids harmalol, harmol and harman detected by means of thin-layer chromatography as well as a number of N,N-dimethyltryptamine alkoloids (DMT). This tea is known in Germany under the brand names "Santo Daime" or Vegetable Union-tea.".