Yerba mate: Is it safe to drink?

A friend suggested that I try yerba mate tea to boost my energy. What is yerba mate? And what do researchers know about it?

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Mayo Clinic dietitian Katherine Zeratsky, R.D., L.D., and colleagues answer select questions from readers.

Answer

Yerba mate is a tropical plant. Yerba mate leaves and twigs can be steeped in hot water to make a tea-like beverage known simply as mate. In fact, yerba mate is widely available in health food stores and online. Proponents of yerba mate say that it can relieve fatigue, promote weight loss, ease depression and headaches, and help treat various other conditions. However, yerba mate contains enough caffeine to raise your heart rate and blood pressure, as well as cause fluctuations in your blood sugar level. Even more concerning is a possible association with cancer. Some studies indicate that prolonged use of yerba mate increases the risk of various types of cancer, including cancer of the mouth, esophagus and lungs. Smoking in combination with yerba mate seems to greatly increase the cancer risk. Until researchers know more about the risks, you may want to avoid yerba mate.