Overview

Rhubarb is a plant in the Rheum genus. The root, which is found in teas and dietary supplements, is commonly used for the short-term treatment of constipation. Common side effects of rhubarb root may include cramping, stomach pain, diarrhea, nausea, or vomiting. Serious side effects of rhubarb root are uncommon and typically only occur when it is overused or misused. The cooked stalks of the plant are often eaten as a vegetable. They are usually well tolerated, although they may increase the risk for kidney stones in some people. The leaf of the plant is toxic and should not be eaten. Before taking rhubarb, tell your health care provider about any health conditions you have or medicines you are taking.

Uses

What is rhubarb used for?

Rhubarb stalks are commonly cooked and eaten as food. Rhubarb roots are commonly used for constipation. Although they may also be used for other reasons, their benefits are not well defined.

Note: Rhubarb is regulated as a food by the FDA. Learn more about the regulation of foods and beverages here. The FDA has not reviewed rhubarb supplements for safety and effectiveness. Learn more about dietary supplements here.

How does rhubarb work (mechanism of action)?

Rhubarb refers to plants in the Rheum genus. The leaves of the plant are considered toxic and should not be eaten. Rhubarb stalks, on the other hand, are often cooked and eaten as a vegetable. Rhubarb roots are used to make teas and dietary supplements. Most dietary supplements contain the roots of two specific plants that are both known as Chinese rhubarb – Rheum palmatum and Rheum officinale. Each part of the plant contains different chemicals that have different effects on the body.

Rhubarb roots contain chemicals called anthraquinones. These chemicals are a type of stimulant laxative, meaning that they stimulate the lining of your intestines to help push stool (poop) through faster. Stimulant laxatives work quickly and usually help to bring on a bowel movement within about 12 hours. However, they may also cause diarrhea and cramping. Regular use of rhubarb root may increase your risk of side effects (see the Side Effects section for more information). Stimulant laxatives, including rhubarb root, should not be used for more than a week unless your health care provider tells you to do so.

Although there is interest in using rhubarb root for other reasons, its benefits for any other use are not well researched or defined.

Herbal products, like rhubarb, naturally contain many different chemicals. The amounts of each chemical in a specific rhubarb product may vary. Some, none, or all of these chemicals may have effects on the body. These effects may change depending on how much of each chemical is found in the product you are using.

How should I store rhubarb?

You should store rhubarb according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.

Side Effects

What are the most common side effects of rhubarb?

The most common side effects of rhubarb are listed below. These side effects may vary depending on the dose you are taking or the specific product you are using. Tell your health care provider if you have any of these side effects that bother you.

• Cramping or stomach pain
• Diarrhea
• Nausea

There may be other side effects of rhubarb that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of rhubarb?

While less common, the most serious side effects of rhubarb are described below, along with what to do if they happen.

Severe Allergic Reactions. Rhubarb may cause allergic reactions, which can be serious. Stop using rhubarb and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching or skin rash
• Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain

Low Potassium Levels (Hypokalemia). Rhubarb root can cause diarrhea. This can lead to a low potassium level, which can be serious. Your risk may be higher if you use certain medicines or take rhubarb root regularly for a while. Call your health care provider if you have any of the following symptoms of a low potassium level.

• Weakness
• Unusual tiredness
• Muscle cramps or twitching
• Constipation

Kidney Stones.Uncooked rhubarb stalks contain large amounts of oxalates, which can increase the risk of kidney stones. Cooking the stalks reduces the oxalate levels so that they are safe to eat. However, they may still increase your risk of kidney stones, especially if you have had kidney stones in the past. Drinking plenty of water while eating cooked rhubarb stalks can help prevent kidney stones. Tell your health care provider right away if you have severe pain in your side or back or have blood in your urine (pee). Rhubarb roots, which are used to make teas and dietary supplements, do not increase the risk for kidney stones.

Precautions

Who should not use rhubarb?

Allergies to Ingredients. People who are allergic to any of the following should not use rhubarb.

• Rheum officinale
• Rheum palmatum
• Rhubarb
• Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific rhubarb products they stock.

Digestive Tract Problems. Tell your health care provider if you have constipation with stomach pain, nausea, or vomiting. These could be symptoms of a more serious condition. Rhubarb root should not be used if you have certain stomach problems, including a gut blockage or tear, ulcerative colitis, Crohn’s disease, appendicitis, poop stuck in your digestive tract (fecal impaction), bleeding in your digestive tract or rectal bleeding, or blood in your poop.

What should I know about rhubarb before using it?

Rhubarb stalks are cooked and eaten as food. Rhubarb root is available as a tea and a dietary supplement. Rhubarb products cannot be marketed to treat or cure a disease.

Read and follow the directions on the specific product you are using, or use it as recommended by your health care provider.

Keep rhubarb out of the reach of children. Children under 12 years of age may be at an increased risk for side effects from rhubarb root. Speak to a health care provider about the possible risks.

In rare cases, taking rhubarb root has caused parts of the colon in some people to become darker, a condition called melanosis coli. This color change does not cause any symptoms, but it is not clear whether it can affect your health. Your risk of developing this condition is higher if you use rhubarb root regularly for a long time. Speak to your health care provider if you have concerns.

Rhubarb root may cause your urine to turn a pinkish-red or bright yellow color. This change in color is harmless and should go away after you stop taking rhubarb root.

If you are using rhubarb root for constipation, you should not take it for more than one week unless your health care provider tells you to do so. If you have rectal bleeding or blood in your poop, stop taking rhubarb and contact your health care provider right away.

The leaves and uncooked stalks of the rhubarb plant can be toxic when eaten. These parts of the plant contain chemicals called oxalates that can burn your mouth, throat, and stomach and also cause kidney stones. Cooking the stalks reduces the amount of oxalates, making them safe to eat. But the leaves should never be eaten. Most dietary supplements and teas that contain rhubarb are made from the roots of the plant, which do not contain large amounts of oxalates. It is important to read the label to confirm which part of the plant was used to make that product.

Herbal products, such as rhubarb, naturally contain many different chemicals. The amount of each chemical in a specific rhubarb product can change for many reasons, including the area where the plant was grown, the weather during growth, the time of year when it was harvested, and the way the plant was processed after being harvested. If you switch to a new bottle or a different brand, you may not have the same effects or side effects because of this variability. Talk to your health care provider if you have questions or concerns.

Rhubarb root is available in many different forms, including as a tea, dried ground powder, or capsule. Each of these forms may contain different amounts of the chemicals that are naturally found in the plant.

The FDA has not tested rhubarb products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

What should I tell my health care provider before using rhubarb?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if rhubarb is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions.Tell your health care provider if you have any of the following.

• A new change in your bowel habits that lasts for two weeks or more
• An electrolyte imbalance, including low potassium levels
• Kidney or liver problems

Other Medicines and Supplements.Rhubarb may interact with other medicines and supplements. Before taking rhubarb, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how rhubarb could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. It is not known if rhubarb root passes into breast milk, but it may cause harm to an infant or a small child. Tell your health care provider if you are breastfeeding or plan to breastfeed.

Interactions

Does rhubarb interact with foods or drinks?

There are no known interactions between rhubarb and foods or drinks.

It is unknown if drinking alcohol will affect rhubarb.

Does rhubarb interact with medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking rhubarb root.

• A corticosteroid, such as dexamethasone, methylprednisolone, or prednisone, which is a medicine for certain inflammatory conditions
• A diuretic, also called a water pill, which is a medicine used to reduce edema (fluid retention) and blood pressure
• A medicine used to control your heart rate or rhythm (antiarrhythmic)
• Digoxin (Lanoxin), which is a medicine used to treat irregular heartbeat and some types of heart failure
• Lily-of-the-valley, which is a supplement that may be used for certain heart problems
• A laxative to clean out your bowel (bowel prep), such as before a colonoscopy
• Any other stimulant laxative, such as senna or bisacodyl
• Large amounts of licorice candies, teas, or supplements

Rhubarb root may affect how well some other medicines work. Tell your health care provider about all medicines that you take or have recently taken.

The interactions between rhubarb and medicines are not fully understood. As with most dietary supplements, research on drug interactions with rhubarb is incomplete. Always check with your health care provider before taking rhubarb with any medicines.

Dosing

What should I do if I accidentally use too much rhubarb?

If you or someone else has used too much rhubarb, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

Cooked rhubarb stalks are commonly eaten as food. Rhubarb root is made into teas and dietary supplements. Read the product label closely and speak to a health care provider about how to take rhubarb safely. Do not take double or extra doses, even if you miss a dose.