Mescal Bean Toxicity

The Full Story

If you have ever sprouted a plant from seed and you observed two little leaves emerged from the seed—that was a dicot. The Texas mountain laurel (Sophora speciose) is a dicot in the same genetic family as the pea plant. Just like peas, the Texas mountain laurel tree produces pods containing seeds, and these are known as mescal beans. However, unlike peas these are not edible. The plants of the genus Sophora are commonly called “necklace pods” for their long pods that hang as they grow and somewhat resemble an unclasped beaded necklace. Mescal beans are actually used to make jewelry. The beans come in different shades of bright reds to yellows. Like most beans, when they are dried they are hard and last a long time before they start to rot.

The Texas mountain laurel is native to southwest North America. Native American tribes have used mescal beans during ceremonies and have reported hallucinations. Other ritual components may have contributed to developing hallucinations, such as fasting, physical exertion, and lack of sleep.

Mescal beans by themselves can cause hallucinations, but these are accompanied by many other undesirable side effects such as hours of severe vomiting, abdominal pain, low blood pressure, rapid heart rate, confusion, agitation, and tremors. Poisoning with mescal beans is similar to nicotine poisoning because the cytisine compound in mescal beans works on the same receptors that nicotine does. Because of the activity at nicotine receptors, cytisine found in mescal beans has been used for smoking cessation. Despite the similarity in name, mescal beans do not contain mescaline, which is a hallucinogenic alkaloid found in certain species of cactus.

Mescal beans are easy to obtain without restriction. The desired effect of hallucination is not likely to occur without unwanted toxic effects that could lead to hospitalization.

If someone has tasted or eaten a mescal bean, log onto the webPOISONCONTROL® online tool for guidance or call Poison Control at 1-800-222-1222. Whether you log on or call, expert assistance is available 24 hours a day.

Pela Soto, PharmD, BSHS Pharmacogenomics, BS Microbiology
Certified Specialist in Poison Information