The most serious risk of ayahuasca comes from its own mechanism. The harmala alkaloids in the vine inhibit the enzyme MAO-A, and while that enzyme is blocked, medicines and drugs that raise serotonin can accumulate to dangerous levels. The result can be serotonin syndrome, which can be fatal (Brito-da-Costa et al., 2020). Most of the deaths and emergencies discussed in the literature involve a combination: with medication, with other drugs, or with plants added to the brew.
This page is information, not medical advice. If you take any prescription medicine, the person to ask is your own doctor or pharmacist, with the word “MAO inhibitor” in the question.
Medication and drugs that do not mix
Researchers warned as early as 1998 that combining ayahuasca with SSRI antidepressants could cause severe reactions. They described cases of agitation, confusion, heavy sweating, rising temperature and muscle rigidity in people who were taking an SSRI (Callaway and Grob, 1998). A 2025 review of DMT-related deaths concluded that combinations including MAO inhibitors are among those causing the most harm on the serotonin toxicity spectrum (Pullen et al., 2025).
Combinations named in the literature as dangerous or problematic:
| Group | Examples | Why it matters |
|---|---|---|
| SSRI and SNRI antidepressants | fluoxetine, sertraline, venlafaxine | serotonin syndrome |
| Other antidepressants | tricyclics, mirtazapine, other MAO inhibitors | serotonin and blood pressure effects |
| Lithium | named as problematic in reviews | |
| Migraine medicines | triptans | serotonin effects |
| Parkinson medicines | levodopa | named as problematic in reviews |
| Stimulants and party drugs | cocaine, amphetamine, MDMA | serotonin and blood pressure effects |
| Other psychedelics | 5-MeO-DMT, other tryptamines | present in several fatal cases |
The list is not complete. Some cough medicines, opioid painkillers and herbal products such as St John's wort also act on serotonin. Some antidepressants, fluoxetine in particular, stay in the body for weeks after the last dose, and stopping medication on your own carries its own risks. Retreats sometimes give their own rules for how long to stop medication beforehand. That decision belongs with a doctor.
Food and the dieta
Old, irreversible MAO inhibitor medicines require a strict diet, because tyramine in aged cheese, cured meat and similar foods can raise blood pressure sharply. Harmine and harmaline inhibit MAO-A reversibly and for a shorter time. How large the food risk is with an actual ayahuasca brew has not been measured well. The traditional dieta that many retreats prescribe covers some of the same foods, but it was not designed as a tyramine protocol. Both the medication and the food question are open; err on the side of caution.
Who should not drink ayahuasca
According to the reviews cited on this page, these groups face clearly higher risk:
- People who take any of the medicines in the table above, or who stopped them recently.
- People with a personal or family history of psychosis, schizophrenia or bipolar disorder. In reviewed case reports, psychotic episodes after ayahuasca mostly occurred in people with such a history or who had also used other drugs.
- People with heart disease or high blood pressure. Ayahuasca raises blood pressure and changes heart rate.
There is little or no safety data for people with a history of seizures, for pregnancy and breastfeeding, or for anyone under 18. The only sensible conclusion for those groups is not to take part.
In the Global Ayahuasca Survey, physical adverse effects were more frequent among people with existing physical health conditions, people who started at an older age, and people who drank without supervision (Bouso et al., 2022). 2.3 percent of respondents said they had needed medical attention for physical effects afterwards.
What is known about deaths
Deaths around ayahuasca ceremonies are reported regularly in the news, but well-documented cases in the scientific literature are few, and most involve more than the brew alone.
- A 2020 review found two deaths in the literature involving these substances: one attributed to acute nicotine poisoning from tobacco used in the ceremony, and one with an undetermined cause in which 5-MeO-DMT was found alongside DMT and the harmala alkaloids. The authors note that no death had been directly attributed to ayahuasca itself (Brito-da-Costa et al., 2020).
- A 2025 review lists earlier cases including a 19-year-old in Colombia who died after drinking yagé in a ritual, with scopolamine also found, pointing to an added plant (Pullen et al., 2025).
- In January 2025 the US Embassy in Peru advised its citizens not to use ayahuasca or kambo, after several US citizens died or became seriously ill in 2024. The embassy pointed to remote locations far from hospitals.
“Not directly attributed to the brew” does not mean safe. The reviews above describe deaths involving added plants and combinations with other drugs or medication. In a remote retreat, a manageable emergency can become fatal simply because help is hours away.
Practical safety points
- Tell the organisers about every medicine and supplement you take, and expect them to ask. A retreat that does not ask is a warning sign.
- Know where the nearest hospital is and how long it takes to get there.
- Never combine ayahuasca with other drugs, including tobacco preparations, kambo or 5-MeO-DMT offered in the same week.
- Do not drink a brew of unknown origin, and never prepare one yourself.
- Have someone outside the retreat who knows where you are.
Next: how to judge a retreat or ceremony, and what the law says where you live.