Yerba mate, also called mate, is a popular drink similar to coffee or tea. It’s made from the leaves of the Ilex paraguariensis plant and contains caffeine.

Caffeine and other chemicals in yerba mate can stimulate the brain, heart, muscles lining blood vessels, and other parts of the body.

People use yerba mate for athletic performance, memory and thinking skills, headache, fatigue, and many other conditions, but there is no good scientific evidence to support these uses.

Using yerba mate long-term, especially with alcohol or nicotine, has been linked to an increased risk of various types of cancer, including stomach, kidney, lung, and mouth cancer. Don’t confuse yerba mate with caffeine or other caffeine sources, such as green tea, black tea, and guarana.

There is interest in using yerba mate for a number of purposes, but there isn’t enough reliable information to say whether it might be helpful.

When taken by mouth:Yerba mate is possibly safe when used for up to 12 weeks. Yerba mate contains caffeine, which can cause side effects such as insomnia, upset stomach, increased heart rate, and others.

Yerba mate is possibly unsafe when taken in large amounts or for long periods of time. Drinking large amounts of yerba mate (1-2 liters daily) for a long time increases the risk of some types of cancer. This risk is especially high for people who smoke or drink alcohol. Consuming more than 10 cups daily might also increase the risk of serious caffeine-related side effects.

Special precautions & warnings:

Pregnancy: Yerba mate is possibly unsafe when taken by mouth during pregnancy. Yerba mate seems to increase the risk of getting cancer. It’s not known whether that risk is transferred to the fetus. Yerba mate also contains caffeine. Avoid consuming more than 300 mg of caffeine daily (about 6 cups of yerba mate) when pregnant. High doses of caffeine have been linked with miscarriage, premature delivery, and low birth weight.

Breast-feeding: Yerba mate is possibly unsafe when taken by mouth while breast-feeding. It’s not known whether the cancer-causing chemicals in yerba mate pass into breast milk. Also, the caffeine in yerba mate might cause irritability and increased bowel movements in nursing infants.

Children: Yerba mate is possibly unsafe when taken by mouth in children. Yerba mate is linked with an increased risk of some types of cancer.

Alcohol use disorder: Consuming yerba mate with large amounts of alcohol long-term seems to increase the risk of cancer.

Anxiety disorders: The caffeine in yerba mate might make anxiety disorders worse.

Bleeding disorders: Caffeine might slow clotting. The caffeine in yerba mate might make bleeding disorders worse. But so far, this effect has not been reported in people.

Heart conditions: Caffeine in yerba mate can cause irregular heartbeats in certain people. If you have a heart condition, use yerba mate in moderation.

Diabetes: The caffeine in yerba mate might affect blood sugar. Use yerba mate with caution if you have diabetes.

Diarrhea: Yerba mate contains caffeine. The caffeine in yerba mate, especially when taken in large amounts, can worsen diarrhea.

Seizures: Yerba mate contains caffeine. High doses of caffeine might cause seizures or decrease the effects of drugs used to prevent seizures. If you have ever had a seizure, don’t take high doses of caffeine.

Glaucoma: Using yerba mate increases the pressure inside the eye due to the caffeine it contains. The increase in pressure occurs within 30 minutes and lasts for at least 90 minutes. If you have glaucoma, discuss your use of yerba mate with your healthcare provider.

High blood pressure: Yerba mate contains caffeine. Drinking caffeine might increase blood pressure in people with high blood pressure. However, this effect might be less in people who drink caffeine regularly.

Irritable bowel syndrome (IBS): Yerba mate contains caffeine. The caffeine in yerba mate, especially when taken in large amounts, can worsen diarrhea and might worsen symptoms of IBS.

Weak bones (osteoporosis): Yerba mate contains caffeine. Caffeine can increase the amount of calcium that is flushed out in the urine. This might weaken bones. If you have osteoporosis, don’t drink more than 6 cups of yerba mate daily. If you are generally healthy and get enough calcium from your food or supplements, drinking about 8-10 cups of yerba mate daily doesn’t seem to increase the risk of getting osteoporosis.

Smoking: Consuming yerba mate and also smoking long-term seems to increase the risk of getting cancer.

Major

Do not take this combination.

Ephedrine

Stimulant drugs speed up the nervous system. The caffeine in yerba mate is a stimulant drug. Ephedrine is also a stimulant drug. Taking caffeine with ephedrine might cause too much stimulation and sometimes serious side effects and heart problems. Do not take caffeine-containing products and ephedrine at the same time.

Moderate

Be cautious with this combination.

Adenosine (Adenocard)

Yerba mate contains caffeine. The caffeine in yerba mate might block the effects of adenosine, which is used to do a test called a cardiac stress test. Stop consuming yerba mate or other caffeine-containing products at least 24 hours before a cardiac stress test.

Antibiotics (Quinolone antibiotics)

Yerba mate contains caffeine. The body breaks down the caffeine in yerba mate to get rid of it. Some antibiotics can decrease how quickly the body breaks down caffeine. Taking these drugs along with caffeine might increase the risk of side effects including jitteriness, headache, and increased heart rate.

Carbamazepine (Tegretol)

The caffeine in yerba mate can decrease the effects of carbamazepine. Taking yerba mate with carbamazepine might decrease the effects of carbamazepine and increase the risk of seizures in some people.

Cimetidine (Tagamet)

Yerba mate contains caffeine. The body breaks down caffeine to get rid of it. Cimetidine can decrease how quickly the body breaks down caffeine. Taking cimetidine along with yerba mate might increase the chance of caffeine side effects including jitteriness, headache, fast heartbeat, and others.

Clozapine (Clozaril)

The body breaks down clozapine to get rid of it. The caffeine in yerba mate seems to decrease how quickly the body breaks down clozapine. Taking yerba mate along with clozapine can increase the effects and side effects of clozapine.

Dipyridamole (Persantine)

Yerba mate contains caffeine. The caffeine in yerba mate might block the effects of dipyridamole. Dipyridamole is often used by doctors to do a test on the heart called a cardiac stress test. Stop consuming yerba mate or other caffeine-containing products at least 24 hours before a cardiac stress test.

Disulfiram (Antabuse)

Yerba mate contains caffeine. The body breaks down caffeine to get rid of it. Disulfiram can decrease how quickly the body gets rid of caffeine. Taking yerba mate along with disulfiram might increase the side effects of caffeine including jitteriness, irritability, and others.

Estrogens

Yerba mate contains caffeine. The body breaks down caffeine to get rid of it. Estrogens can decrease how quickly the body breaks down caffeine. Estrogens might increase the levels of caffeine and increase the risk of caffeine side effects, such as jitteriness, headache, and fast heartbeat.

Ethosuximide (Zarontin)

Ethosuximide is a drug used to treat seizures. The caffeine in yerba mate can decrease the effects of ethosuximide. Taking yerba mate with ethosuximide might decrease the effects of ethosuximide and increase the risk of seizures in some people.

Felbamate (Felbatol)

Felbamate is a drug used to treat seizures. The caffeine in yerba mate might decrease the effects of felbamate. Taking yerba mate with felbamate might decrease the effects of felbamate and increase the risk of seizures in some people.

Flutamide (Eulexin)

The body breaks down flutamide to get rid of it. The caffeine in yerba mate might decrease how quickly the body gets rid of flutamide. This could cause flutamide to stay in the body too long and increase the risk of side effects.

Fluvoxamine (Luvox)

The body breaks down the caffeine in yerba mate to get rid of it. Fluvoxamine can decrease how quickly the body breaks down caffeine. Taking yerba mate along with fluvoxamine might increase caffeine levels in the body and increase the risk of caffeine side effects.

Lithium

The caffeine in yerba mate can increase how quickly your body gets rid of lithium. If you take products that contain caffeine and you take lithium, stop taking caffeine products slowly. Stopping yerba mate too quickly can increase the side effects of lithium.

Medications for asthma (Beta-adrenergic agonists)

Yerba mate contains caffeine. Caffeine can stimulate the heart. Some medications for asthma can also stimulate the heart. Taking caffeine with some medications for asthma might cause too much stimulation and cause heart problems.

Medications for depression (MAOIs)

Yerba mate contains caffeine. There is some concern that caffeine can interact with certain medications, called MAOIs. If caffeine is taken with these medications, it might increase the risk for serious side effects including fast heartbeat and very high blood pressure.

Some common MAOIs include phenelzine (Nardil), selegiline (Zelapar), and tranylcypromine (Parnate).

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)

Yerba mate contains caffeine. Caffeine might slow blood clotting. Taking yerba mate along with medications that also slow blood clotting might increase the risk of bruising and bleeding.

Midazolam (Versed)

The body breaks down midazolam to get rid of it. Yerba mate might decrease how quickly the body breaks down midazolam. Taking yerba mate along with midazolam might increase the effects and side effects of midazolam.

Nicotine

Yerba mate contains caffeine. Caffeine can stimulate the heart. Nicotine can also stimulate the heart. Taking caffeine with nicotine might cause too much stimulation and cause heart problems, such as increased heart rate or blood pressure.

Pentobarbital (Nembutal)

The stimulant effects of the caffeine in yerba mate can block the sleep-producing effects of pentobarbital.

Phenobarbital (Luminal)

Phenobarbital is a drug used to treat seizures. Caffeine in yerba mate might decrease the effects of phenobarbital and increase the risk of seizures in some people.

Phenylpropanolamine

Yerba mate contains caffeine. Caffeine can stimulate the body. Phenylpropanolamine can also stimulate the body. Taking yerba mate and phenylpropanolamine together might cause too much stimulation and increase heartbeat and blood pressure and cause nervousness.

Phenytoin (Dilantin)

Phenytoin is a drug used to treat seizures. Caffeine in yerba mate can decrease the effects of phenytoin. Taking yerba mate with phenytoin might decrease the effects of phenytoin and increase the risk of seizures in some people.

Riluzole (Rilutek)

The body breaks down riluzole to get rid of it. Taking yerba mate can decrease how fast the body breaks down riluzole and increase the effects and side effects of riluzole.

Sedative medications (Benzodiazepines)

Benzodiazepines are drugs that cause sleepiness and drowsiness. The caffeine in yerba mate might increase the breakdown of benzodiazepines. This might reduce the effects of benzodiazepines. Do not use yerba mate if you are taking benzodiazepines.

Stimulant drugs

Stimulants, such as amphetamines and cocaine, speed up the nervous system. By speeding up the nervous system, stimulant medications can increase blood pressure and speed up the heartbeat. Yerba mate contains caffeine. Caffeine can also speed up the nervous system. Taking yerba mate along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure.

Theophylline

Yerba mate contains caffeine. Caffeine works similarly to theophylline. Caffeine can also decrease how quickly the body gets rid of theophylline. Taking yerba mate along with theophylline might increase the effects and side effects of theophylline.

Valproate

Valproate is a drug used to treat seizures. Caffeine in yerba mate might decrease the effects of valproate and increase the risk of seizures in some people.

Verapamil (Calan, others)

The body breaks down the caffeine in yerba mate to get rid of it. Verapamil can decrease how quickly the body gets rid of caffeine. Drinking yerba mate and taking verapamil can increase the risk of caffeine side effects.

Water pills (Diuretic drugs)

Yerba mate contains caffeine. Caffeine, especially in large amounts, can reduce potassium levels in the body. “Water pills” can also decrease potassium levels in the body. Taking large amounts of caffeine along with “water pills” might decrease potassium levels too much.

Minor

Be watchful with this combination.

Alcohol (Ethanol)

The body breaks down the caffeine in yerba mate to get rid of it. Alcohol can decrease how quickly the body breaks down caffeine. Taking yerba mate along with alcohol might increase caffeine levels and the risk for caffeine side effects such as jitteriness, headache, and fast heartbeat.

Birth control pills (Contraceptive drugs)

The body breaks down the caffeine in yerba mate to get rid of it. Birth control pills can decrease how quickly the body breaks down caffeine. Taking yerba mate along with birth control pills can cause jitteriness, headache, fast heartbeat, and other side effects.

Fluconazole (Diflucan)

Yerba mate contains caffeine. The body breaks down caffeine to get rid of it. Fluconazole might decrease how quickly the body gets rid of caffeine. This could increase levels of caffeine in the body and increase the risk of caffeine side effects.

Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)

Some medications are changed and broken down by the liver. Yerba mate might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

Medications for diabetes (Antidiabetes drugs)

Yerba mate contains caffeine. Caffeine can either increase or decrease blood sugar. Diabetes medications are used to lower blood sugar. Taking some medications for diabetes along with caffeine might change the effects of the diabetes medications. Monitor your blood sugar closely. The dose of your diabetes medication might need to be changed.

Medications that decrease break down of other medications by the liver (Cytochrome P450 CYP1A2 (CYP1A2) inhibitors)

Yerba mate is changed and broken down by the liver. Some drugs decrease how quickly the liver changes and breaks down yerba mate. This could change the effects and side effects of yerba mate.

Metformin (Glucophage)

Yerba mate contains caffeine. Metformin can decrease how quickly the body breaks down caffeine. Taking yerba mate with metformin might increase caffeine levels in the body and increase the effects and side effects of caffeine.

Methoxsalen (Oxsoralen)

Yerba mate contains caffeine. Methoxsalen can decrease how quickly the body breaks down caffeine. Taking caffeine along with methoxsalen might increase caffeine levels in the body and increase the effects and side effects of caffeine.

Mexiletine (Mexitil)

Yerba mate contains caffeine. Mexiletine can decrease how quickly the body breaks down caffeine. Taking mexiletine along with yerba mate might increase the risk of caffeine side effects.

Terbinafine (Lamisil)

Yerba mate contains caffeine. Terbinafine can decrease how quickly the body gets rid of caffeine and increase the risk of caffeine side effects, such as jitteriness, increased heartbeat, and others.

Tiagabine (Gabitril)

Yerba mate contains caffeine. Taking caffeine over a period of time along with tiagabine can increase the amount of tiagabine in the body. This might increase the effects and side effects of tiagabine.

Ticlopidine (Ticlid)

Ticlopidine can decrease how quickly the body gets rid of caffeine. Taking yerba mate along with ticlopidine might increase the caffeine side effects, including jitteriness, hyperactivity, irritability, and others.

Bitter orange

Do not use yerba mate with bitter orange. The combination might overstimulate the body, resulting in increased blood pressure and heart rate, even in people with normal blood pressure.

Caffeine-containing herbs and supplements

Yerba mate contains caffeine. Taking it along with other supplements that contain caffeine might increase caffeine side effects. Examples of supplements that contain caffeine include black tea, coffee, green tea, and guarana.

Calcium

Drinking large amounts of yerba mate can increase the amount of calcium that is flushed out in the urine. This might lower calcium levels in the body.

Cordyceps

Yerba mate contains caffeine. Cordyceps might increase how quickly the body gets rid of caffeine. This might decrease the effects of caffeine.

Creatine

Combining caffeine, ephedra, and creatine might increase the risk of serious unwanted side effects. One athlete who used this combination, as well as some other supplements to improve performance, suffered a stroke. Researchers worry the stroke might have been caused by the supplements.

Danshen

Yerba mate contains caffeine. Danshen can decrease how quickly the body gets rid of caffeine. Drinking yerba mate and taking danshen might increase the risk of side effects, including jitteriness, headache, and an increased heartbeat.

Echinacea

Yerba mate contains caffeine. Echinacea can decrease how quickly the body gets rid of caffeine. Drinking yerba mate and taking echinacea might increase the risk of side effects, including jitteriness, headache, and an increased heartbeat.

Ephedra

Yerba mate contains caffeine. Using ephedra with caffeine might increase the risk of serious life-threatening or disabling conditions such as hypertension, heart attack, stroke, seizures, and death. Avoid this combination.

Genistein-containing herbs and supplements

Yerba mate contains caffeine. A chemical called genistein can decrease how quickly the body gets rid of caffeine. Taking yerba mate and taking genistein might increase the risk of caffeine side effects. Examples of supplements that contain genistein include cumin, dyer’s broom, kudzu, red clover, and soy.

Herbs and supplements that slow blood clotting

Yerba mate might slow blood clotting and increase the risk of bleeding. Taking it with other supplements with similar effects might increase the risk of bleeding in some people. Examples of supplements with this effect include garlic, ginger, ginkgo, nattokinase, and Panax ginseng.

Iron

Taking yerba mate might reduce how much iron the body absorbs from food or supplements.

Kudzu

Yerba mate contains caffeine. Kudzu can decrease how quickly the body gets rid of caffeine. Drinking yerba mate and taking kudzu might increase the risk of side effects, including jitteriness, headache, and an increased heartbeat.

Magnesium

Drinking large amounts of yerba mate can increase the amount of magnesium that is flushed out in the urine. This might lower magnesium levels in the body.

Melatonin

Yerba mate contains caffeine. Taking caffeine and melatonin together can increase melatonin levels. Caffeine can also increase natural melatonin levels in healthy people.

There are no known interactions with foods.

Yerba mate is commonly consumed as a tea by steeping yerba mate leaf in boiling water. Speak with a healthcare provider to find out what dose might be best for a specific condition.

Chimarrao, Green Mate, Hervea, Ilex, Ilex paraguariensis, Jesuit’s Brazil Tea, Jesuit’s Tea, Maté, Maté Folium, Paraguay Tea, St. Bartholemew’s Tea, Thé de Saint Barthélémy, Thé des Jésuites, Thé du Brésil, Thé du Paraguay, Yerbamate, Yerba Mate, Yerba Maté.

To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.

1. Pagliosa CM, Vieira FGK, Dias BV, Brognoli Franco VK, Ramos HP, da Silva EL. Ilex paraguariensis (A. St.-Hil.) leaf infusion decreases iron absorption in patients with hereditary hemochromatosis: a randomized controlled crossover study. Food Funct 2021;12:7321-7328. View abstract.
2. Medeiros MS, Schumacher-Schuh AF, Altmann V, Rieder CRM. A Case-Control Study of the Effects of Chimarrão (Ilex paraguariensis) and Coffee on Parkinson’s Disease. Front Neurol 2021;12:619535. View abstract.
3. Feltrin C, Farias IV, Sandjo LP, Reginatto FH, Simões CMO. Effects of Standardized Medicinal Plant Extracts on Drug Metabolism Mediated by CYP3A4 and CYP2D6 Enzymes. Chem Res Toxicol 2020;33:2408-2419. View abstract.
4. Gebara KS, Gasparotto Junior A, Palozi RAC, et al. A Randomized Crossover Intervention Study on the Effect a Standardized Maté Extract (Ilex paraguariensis A. St.-Hil.) in Men Predisposed to Cardiovascular Risk. Nutrients 2020;13:14. View abstract.
5. Cozma-Petrut A, Loghin F, Miere D, Dumitrascu DL.Diet in irritable bowel syndrome: What to recommend, not what to forbid to patients! World J Gastroenterol. 2017;23:3771-3783. View abstract.
6. Rao SS. Current and emerging treatment options for fecal incontinence. J Clin Gastroenterol. 2014;48:752-64.
   View abstract.
7. Gómez-Juaristi M, Martínez-López S, Sarria B, Bravo L, Mateos R. Absorption and metabolism of yerba mate phenolic compounds in humans. Food Chem. 2018;240:1028-1038. View abstract.
8. Chaves G, Britez N, Oviedo G, et al. Heavy drinkers of Ilex paraguariensis beverages show lower lipid profiles but higher body weight. Phytothe