Nopal cactus is considered most safe when eaten as a food instead of a supplement; this has the fewest side effects. While supplements are considered to be possibly safe, more evidence is needed.

People can use nopal cactus in a variety of sweet and savory dishes and drinks. People also use it in traditional medicine to treat glaucoma and other conditions. Read more here.

When True Nopal Ventures launched, it was the only cactus-water producer in the world. Within 90 days, its product went national. Now, Zummo said, there are as many as a dozen around the globe.

The nopal, also known as the prickly pear cactus, is more than just another succulent in the desert landscape of Mexico and the U.S. Southwest -- it's also a significant food source.