This Acanthaceae, known as toe negro (cf. Brugmansia suaveolens) , is used by the Colombian Kokama Indians both as an ayahuasca additive and as a psychoactive substance in its own right. For this purpose, ten leaves are boiled for seven hours over a low flame. The effects are said to be strong. A person loses his or her vision for three days, but during this time he or she can communicate with the spirit of the plant (Schultes 1972, 139*). Chemical studies of the plant have demonstrated that the leaves are devoid of alkaloids (Ott 1993, 402*). The plant is added to ayahuasca only when it is intended for use in "witchcraft" (Duke and Vasquez 1994, 167*).