How Do You Use Senna Tea, and Is It Safe?

Senna tea contains active plant-based substances that help relieve constipation. The tea is made from the leaves of the senna plant. The most commonly used species are Cassia acutifolia or Cassia angustifolia.

Senna is also sold as a supplement and approved by the U.S. Food and Drug Administration (FDA) as an over-the-counter laxative. Senna may be touted for losing weight and detoxing, but these uses aren't backed by research. Using senna tea for anything other than short-term constipation treatment may cause health problems.

What Is Senna?

Senna is a flowering plant with beneficial chemicals extracted from its leaves. If you have fresh senna leaves (the senna plant grows wild in some parts of the United States), you can dry them and make senna tea by steeping the dried leaves in hot water. Most people interested in senna tea make the beverage by purchasing powdered leaves.

Uses

Multiple studies have tested the effects of senna in powder or capsule form. However, there are very few studies about the potential benefits of drinking senna tea.

Most of the research studies on the health benefits of senna focus on its use in the treatment of constipation and other gastrointestinal disorders.

Constipation

Senna tea is most commonly used for occasional constipation. In a systematic review (a summary of medical literature on a specific topic) of 41 studies, evidence emerged supporting the use of senna as a first-line choice for use in constipation.

Researchers have found that the active compounds in senna have a strong laxative effect. They work by promoting colon contractions and bowel movements.

Senna also prevents water and electrolytes from being reabsorbed from the colon. This increases the amount of fluid in the intestines and softens the stool.

Adequate doses of senna can vary depending on the product and preparation. Long-term use is not recommended due to the risk of becoming dependent on senna to have a bowel movement and developing other severe side effects.

Colonoscopy Prep

Senna has been used along with other agents (including probiotics) to clean the colon prior to a colonoscopy, a medical procedure used in screening for colon cancer.

Evidence reveals the use of senna, including premedication ahead of a capsule colonoscopy (a visual inspection of the colon using a tiny, swallowed camera), can improve the cleansing of the colon.

Other Gastrointestinal Disorders

Senna is sometimes used for irritable bowel syndrome (IBS). When looking specifically at irritable bowel syndrome with constipation (IBS-C), however, there is minimal research supporting the safe use of senna. More study of its use in IBS is needed.

What Are the Side Effects of Senna?

When senna is used as a short-term treatment of constipation, side effects are generally mild and limited. When taken for an extended period of time or in large amounts, senna may cause more severe health problems.

Common Side Effects

The most common side effects of senna tea include:

• Stomach discomfort
• Cramps
• Diarrhea
• Nausea
• Vomiting
• Bloating

In some cases, senna tea may be used for a longer period of time when a person is under the care of a healthcare provider. Be aware that when used for extended periods of time, senna poses other health risks.

Severe Side Effects

Long-term use of senna, as well as higher doses, have been linked to serious health problems beyond chronic constipation. Severe side effects include:

• Liver injury
• Electrolyte disturbances
• Changes in heart rhythms

Symptoms associated with liver damage when using senna include:

• Jaundice (yellowing of skin)
• Dark or brown urine
• Abdominal pain
• General weakness
• Encephalopathy (brain effects)

Liver damage typically occurs after senna use of three to five months. Most cases of liver damage will heal but permanent damage is possible.

Precautions

Do not take senna tea without first discussing it with a healthcare provider if you have:

• Crohn's disease (a type of irritable bowel disease, or IBD)
• Ulcerative colitis (a type of IBD)
• Appendicitis (inflammation of the appendix)
• Kidney problems
• Heart problems
• Dehydration
• Abdominal pain
• Any condition that causes intestinal obstruction
• An allergy to senna

If you have any type of liver condition, don't use senna before talking with your healthcare provider. Likewise, if you are pregnant or breastfeeding, seek a provider's advice before using senna tea.

Weight Loss

Senna tea is often marketed for weight loss and detoxing your digestive tract. Neither claim is backed by scientific evidence and using senna for weight loss may lead to health problems.

Easing constipation is senna’s only proven health benefit. Using senna (or any other laxative) for weight loss is ineffective and potentially dangerous.

Senna tea has little or no impact on your weight, and if it does, it's temporary. Your body continuously produces stool, so its minimal weight is always part of your total body weight.

Taking senna for weight loss may lead to prolonged use of the laxative, and that can lead to bowel dysfunction.

Using laxatives for weight loss poses another health risk: They may increase your risk of developing an eating disorder.

Researchers reviewed the records of more than 10,000 women diagnosed with an eating disorder. They discovered that using diet pills or laxatives for weight loss made them more likely to also develop an eating disorder.

Though they can't pinpoint exactly why the connection exists, their results suggest that using these substances may be a sign of the early stages of disordered eating.

Interactions

Consult with your healthcare provider before drinking senna tea or taking senna in any form if you take digoxin, estrogens, blood thinners (warfarin), or water pills (diuretics). Senna interacts with these medicines, putting your health at risk by potentially decreasing or increasing their effectiveness.

Senna use can result in decreased levels of potassium. Diuretics can have the same effect on the body; so can other herbs, like licorice and horsetail. None of these should be taken together with senna to prevent low potassium.

Protect your health by reviewing the label and talking with your healthcare provider about the potential interactions between senna and any prescription or over-the-counter medications and dietary supplements you may take.

Dosage: How Much Senna Should I Take?

Senna is widely available in health food stores, vitamin shops, and online. However, there is no standardized dose.

Senna tea is likely safe when used in moderation for up to one week. It may be unsafe to take doses containing more than 34.4 mg of sennosides (senna's primary active ingredient) or use senna for longer than a week. For constipation during pregnancy, it may be safe.

When researchers have studied it for the treatment of general constipation, the usual dose is 15 milligrams (mg) daily. In older adults, 17 mg daily has been used.

Be aware that it can be hard to know how much you're getting in a cup of tea and how it will affect you. If you use fresh leaves and make your own tea, you can't know the dose you might consume.

Many tea sellers list the use of a "proprietary blend" on their product labels. They do not list the amount of each herb in the tea, so you have no way of knowing how much senna it has.

It would still be hard to know the exact dose found in your cup of tea, even if you know the amount of senna in a product. Steeping time and water temperature can change the amount of senna released into the brew.

Supplements should state the dose per recommended serving. But keep in mind that there aren't any guarantees that unregulated supplements contain what's on the label.

When taken in the dose recommended by senna-containing laxative products, senna usually starts working within six to 12 hours after taking it. It is often taken prior to going to bed. This means that you are likely to feel the urge to have a bowel movement in the morning.

Similar Supplements

There are other supplements with similar laxative effects, including:

• Aloe (a cactus-like plant)
• Magnesium (mineral crucial to body functions)
• Rhubarb (a perennial vegetable with fleshy, edible stalks)

Taking senna with these supplements can result in diarrhea and low potassium levels.

Sources of Senna and What to Look For

Senna is usually taken by mouth. It is available as tablets, capsules, powder, tea, and flavored liquids. Avoid taking multiple types of senna at the same time.

Senna is available over the counter (OTC, without a prescription) at drugstores, groceries, and nutrition stores. Senna tablets can also be found online. 

Summary

Senna tea is made from leaves containing active ingredients (sennosides) proven to effectively relieve constipation. This is currently the only safe and effective use of senna.

While it’s safe to use senna tea and other senna products for up to a week, taking it longer or in doses higher than recommended on the label can lead to mild and severe side effects. One of the most common is senna dependency. Drinking senna tea or taking senna products too long impairs colon function, leading to chronic constipation.