Yerba mate, sometimes referred to as mate, is an herbal tea native to South America. The drink, served hot or cold, is promoted by the natural health community as having numerous health benefits.

But despite its many claimed benefits, some researchers have linked yerba mate to certain kinds of cancer.

Keep reading to see what the research says about the benefits and risks of yerba mate.

Yerba mate is an herbal tea that’s made by steeping the twigs and dried leaves of the Ilex paraguariensis plant in hot water. The tea is traditionally served in a gourd and sipped through a filtered metal straw to strain the leftover fragments.

Mate tea is often consumed for its many purported health benefits. It contains nutrients known for their anti-inflammatory and stimulant effects.

Some of the primary antioxidants and nutrients found in yerba mate include:

  • xanthines
  • saponins
  • polyphenols
  • caffeoyl derivatives

The caffeine found in yerba mate has been shown to increase mental focus and energy levels. While it enhances alertness, mate advocates suggest that it doesn’t have the same jittery effects that may accompany drinking a cup of coffee.

Yerba mate is also alleged to:

Though potentially beneficial for the body, research shows that excessive use of yerba mate over a prolonged amount of time is linked to a number of cancers. Some commonly mentioned include:

Polycyclic aromatic hydrocarbon (PAH) is a known carcinogen

Yerba mate tea contains PAH, a known carcinogen also found in grilled meat and tobacco smoke.

Studies show that increased exposure to PAHs can affect the immune, reproductive, and neurological systems. They can also cause developmental effects and increase the risk of cancer.

Drinking very hot mate tea carries higher risks

According to 2009 research, drinking very hot yerba mate tea — at temperatures at or above 147ºF (64ºC) — is associated with a higher risk of cancer than drinking mate tea at a cooler temperature.

Drinking liquids at higher temperatures could damage the respiratory and digestive lining. It could also cause damage to the mucosa. If tobacco and alcohol are also consumed, this could in turn trigger metabolic reactions and further increase the risk of cancer development.

While yerba mate has been suggested to offer a number of health benefits, in excess it may cause a number of side effects.

Similar to coffee and other caffeine products, yerba mate tea may cause:

Proper precautions should also be taken if you drink yerba mate tea and fall under any of the following categories:

  • You’re pregnant and breastfeeding. Because yerba mate has a high concentration of caffeine, drinking mate tea while pregnant can increase the risk of transferring caffeine to the fetus. High doses of caffeine in pregnant women have been linked to miscarriage, low birth weight, and premature birth.
  • You smoke tobacco. Yerba mate together with tobacco may increase the risk of developing cancer.
  • You drink alcohol. Yerba mate consumed by those who drink alcohol is linked to a higher risk of developing cancer.
  • You have an anxiety disorder. Anxiety and nervousness are a side effect of excessive yerba mate tea consumption. Mate’s rich caffeine content can worsen previously diagnosed anxiety disorders.
  • You have irritable bowel syndrome (IBS). Caffeine from yerba mate tea may trigger diarrhea and can potentially worsen IBS symptoms.

Yerba mate is a tea promoted for its anti-inflammatory properties, energy boosts, and rich antioxidant content.

Consuming large quantities of mate tea has been linked to cancer, but more research is necessary to confirm all known side effects.

Before incorporating yerba mate or any other herbal product into your diet, be sure to check with a doctor to ensure there are no negative interactions with your current medications or health status.