Q. I celebrated New Year’s a little too much this year. Is it true that a cactus can help heal a hangover

A. Prickly pear (Opuntia ficus-indica) may indeed help tone down the effects of excessive drinking. In fact, a joint study by researchers at Tulane University in New Orleans and the University of California, San Francisco, found that taking the herb before you head out for a night on the town just might help you avoid the full force of a hangover (Archives of Internal Medicine, 2004, vol. 164, no. 12).

The double-blind crossover study involved 55 healthy young people assigned to take either 1,600 IU of a prickly pear supplement or a placebo five hours before drinking. Then, researchers asked the volunteers to drink 1.75 grams of the alcohol of their choice per kilogram of body weight—about five or six drinks. Two weeks later, the groups switched, with those in the original prickly pear group taking the placebo and vice versa. Overall, the researchers found that taking the supplement significantly reduced three hangover symptoms: nausea, dry mouth, and loss of appetite.

The reason, says study author Jeff Wiese, MD, is that prickly pear lowers C-reactive protein. C-reactive protein is a marker of inflammation that can cause the upset stomach that often comes after a night of drinking. But because both alcohol and prickly pear are mild diuretics, Wiese warns, it’s also a good idea to drink plenty of water to avoid dehydration while you recover.

Prickly pear may be a boon to your health even if you don’t drink alcohol. Other studies have found that taking this desert cactus in supplement form can boost antioxidant levels and help prevent oxidative damage, especially in the brain. It may also protect against ulcers.

This Ask the Expert is written by Kim Erickson, an herbalist living in Las Vegas.