Humans have used peyote for medicinal purposes for thousands of years. In the United States, where peyote use has occurred for at least centuries, the plant is illegal except in strict religious contexts. That said, its illegality in no way negates its effectiveness as a medicine against various ailments.
Peyote as Medicine
Today, peyote is regularly consumed in places like Mexico, the United States, and Canada by native people of these countries. For many centuries, they have harvested and consumed the plant to treat all manner of illnesses. When consumed orally, such as with infusions, it is often used to treat:
- Dental woes
- Digestive tract issues
- Lung illnesses
- Alcoholism 
Peyote is also used in topical form to treat:
Mescaline as Medicine
Mescaline is one of many alkaloids, and the principal psychotropic substance, found in peyote. The practice of extracting mescaline from peyote is common for religious, recreational, and medicinal purposes.
However, like peyote, mescaline is a Schedule I substance, which means very little legitimate scientific research has investigated its medicinal properties, although surveys have been conducted.
A recent inquiry asked respondents suffering from various psychological issues (including post-traumatic stress disorder (PTSD), anxiety, and depression) to judge their experiences with mescaline and how the drug affected their conditions.  The results showed that 68-86% of those who responded said they had experienced improvement in their condition due to a mescaline experience.
As the West relaxes its stance on psychedelic substances, we will begin to see more research into peyote and mescaline. For instance, a company working in psychedelics medicine, MindMed, last year announced that its proposed study of mescaline had been approved by the ethics committee in the region where the study is to take place.
Researchers will be studying the effects that different doses of mescaline have on serotonin 5-HT2A receptors in humans. According to MindMed’s president Dr. Miri Halperin Wernli, their study is the first modern research carried out on mescaline, and they hope to help characterize and clearly describe the effects consumers feel when ingesting the hallucinogen.
For now, most reported medicinal properties of peyote and mescaline are anecdotal. When the law allows for more research, then maybe modern medicine will catch up to the old medicinal ways that use time and results as proof of effectiveness instead of double blinds.
References Albaugh BJ, Anderson PO. Peyote in the treatment of alcoholism among American Indians. Am J Psychiatry. 1974;131(11):1247-1250. [journal impact factor = 18.11; times cited = 99]
 Agin-Liebes G, Haas TF, Lancelotta R, Uthaug MV, Ramaekers JG, Davis AK. Naturalistic use of mescaline is associated with self-reported psychiatric improvements and enduring positive life changes. ACS Pharmacol Transl Sci. 2021;4(2):543-552. [journal impact factor = 3.5; times cited = 7]
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