are often associated with the use of ayahuasca, although these seem to be specific to the culture around Iquitos, Peru, a major center of ayahuasca tourism. In the rainforest, these taboos tend towards the purification of one's self—abstaining from spicy and heavily seasoned foods, excess fat, salt, caffeine, acidic foods (such as citrus) and sex before, after, or during a ceremony. A diet low in foods containing tyramine has been recommended, as the speculative interaction of tyramine and MAOIs could lead to a hypertensive crisis; however, evidence indicates that harmala alkaloids act only on MAO-A, in a reversible way similar to moclobemide (an antidepressant that does not require dietary restrictions). Dietary restrictions are not used by the highly urban Brazilian ayahuasca church União do Vegetal, suggesting the risk is much lower than perceived and probably non-existent. Ceremony and the role of shamans Shamans, curanderos and experienced users of ayahuasca advise against consuming ayahuasca when not in the presence of one or several well-trained shamans. In some areas, there are purported brujos (Spanish for "witches") who masquerade as real shamans and who entice tourists to drink ayahuasca in their presence. Shamans believe one of the purposes for this is to steal one's energy and/or power, of which they believe every person has a limited stockpile. The shamans lead the ceremonial consumption of the ayahuasca beverage, in a rite that typically takes place over the entire night. During the ceremony, the effect of the drink lasts for hours. Prior to the ceremony, participants are instructed to abstain from spicy foods, red meat and sex. The ceremony is usually accompanied with purging which include vomiting and diarrhea, which is believed to release built-up emotions and negative energy. Traditional brew Traditional ayahuasca brews are usually made with Banisteriopsis caapi as an MAOI, while dimethyltryptamine sources and other admixtures vary from region to region. There are several varieties of caapi, often known as different "colors", with varying effects, potencies, and uses. DMT admixtures: Psychotria viridis (Chacruna) – leaves Diplopterys cabrerana (Chaliponga, Chagropanga, Banisteriopsis rusbyana) – leaves Psychotria carthagenensis (Amyruca) – leaves Mimosa tenuiflora (M. hostilis) - root bark Other common admixtures: Justicia pectoralis Brugmansia (Toé) Nicotiana rustica (Mapacho, variety of tobacco) Ilex guayusa, a relative of yerba mate Common admixtures with their associated ceremonial values and spirits: Ayahuma bark: Cannon Ball tree. Provides protection and is used in healing susto (soul loss from spiritual fright