The effects of a single cup of ayahuasca usually begin 30 to 60 minutes after drinking, are strongest between one and two hours, and fade over the next few hours. In a controlled study with experienced volunteers, the psychological effects were first noticed after 30 to 60 minutes, peaked at 60 to 120 minutes and had resolved by 240 minutes (Riba et al., 2001). A review of the pharmacology puts the overall duration at about four to six hours (Brito-da-Costa et al., 2020).
A ceremony lasts longer than that. Most are held at night, and a second cup is often offered once the first has worn down. Counting from the first cup to the moment people can sleep, a ceremony often takes most of the night.
How a ceremony is usually organised
Practices differ between Indigenous traditions, Brazilian churches and retreats for visitors, so this is a general outline drawn from published descriptions. Many ceremonies differ from it.
- Before. Many retreats ask participants to avoid certain foods, alcohol, other drugs and sex for days or weeks beforehand. This is often called the dieta. Some of these rules come from tradition; the medication rules matter for safety and are covered in the safety chapter.
- Opening. Participants sit or lie in a room or open structure, usually with a bucket each. The person leading the ceremony serves the brew, often in small cups.
- The first hours. Nausea builds as the effects start. Songs, called icaros in Peruvian practice, or hymns in Santo Daime churches, are a central part of the night.
- A second cup. Often offered after one to two hours to those who want it.
- Closing. The leader ends the ceremony formally. People stay in the space or go to sleep there.
What people report during the effects
These are the acute effects described in studies and in large numbers of published accounts. They vary a great deal between people and between nights.
- Visual changes. Patterns and images with the eyes closed are typical, often geometric at first. With the eyes open, colours and light can look different.
- Body. Nausea, vomiting, diarrhoea, sweating, shivering, a faster or irregular heartbeat and raised blood pressure. In the Riba study, nausea and altered bodily sensations were the most frequent unpleasant effects.
- Thought and emotion. Vivid memories, strong emotions in either direction, a changed sense of time and a sense that thoughts have their own momentum.
- Fear and confusion. These are common. In the same small study, one of six experienced volunteers had an intensely unpleasant reaction with temporary disorientation and anxiety and withdrew from the study.
Why most people vomit
Vomiting is the rule more than the exception. In the Global Ayahuasca Survey of 10,836 people, 68.2 percent reported vomiting or nausea (Bouso et al., 2022). Many traditions give vomiting a ritual meaning and call it la purga. That is a cultural interpretation. Physically, it means losing fluid in a dark room, in an altered state, often far from medical care.
Practical points that follow from this: there should be water, a bucket, a clear path to a toilet, and someone sober who can help a person who is too disoriented to walk.
A difficult night is not rare
The same survey found that 55.9 percent of respondents reported adverse mental health effects in the weeks or months afterwards. The most common were hearing or seeing things that others did not (28.5 percent) and feeling disconnected or alone (21.0 percent). Such effects were more likely after use outside a religious setting, and among people with a history of anxiety disorders. A place where you cannot leave, where you do not speak the language and where you depend on strangers makes a hard night harder to handle.
Signs that someone needs help beyond reassurance: confusion that does not lift, a very high temperature, muscle stiffness or jerking, chest pain, fainting, or a person who cannot be woken. These can point to serotonin toxicity or another emergency, which needs medical care straight away.
After the ceremony
Effects are normally gone by the next morning, but sleep, appetite and concentration can be off for a day or more. Driving, travel on difficult roads and swimming in rivers on the following day are bad ideas. If you take regular medication, follow what your doctor told you before the ceremony about when to restart it.
Read about the risks and interactions before anything else, and about how retreats differ.