Health Benefits of Senna

Senna, scientifically known as Senna alexandrina, is an herb most commonly used to treat certain types of constipation. The plant can grow to about 6 feet tall and has a light green, hairy stem, dark green leaves, and pale yellow flowers.

Senna contains compounds called anthraquinones that give the plant its laxative effect. This may also make the herb useful for clearing the bowels before a colonoscopy, treating some irritable bowel syndrome (IBS) symptoms, and relieving hemorrhoid symptoms.

Preliminary research suggests senna could have antimicrobial and hypoglycemic (blood sugar-lowering) properties that might support the treatment of conditions like skin infections, diabetes, and obesity.

The herb is safe to take in appropriate doses, but it may have risks when taken in large doses or continuously over a long period.

Relieves Constipation

Senna is a medically approved remedy for treating short-term constipation. The herb is a stimulant laxative, which means it works by activating contractions in the intestines to prompt a bowel movement.

Expert guidelines for constipation management list senna-based laxatives as an evidence-backed method for treating chronic idiopathic constipation (or long-term constipation without a clear cause). Senna also seems to help relieve constipation related to opioid use.

Aids Colonoscopy Prep

Due to senna's stool-softening properties, medical experts often recommend using senna to clear the bowels before surgery and other medical procedures—like a colonoscopy. The anthraquinones (compounds with a laxative effect) naturally found in senna help increase the amount of fluids in the intestines, which softens the stool, allowing the bowels to fully clear.

Studies have shown that senna is safe for children and adults for pre-surgical bowel clearing. Sometimes, you might combine senna with other treatments, like probiotics, to support this process.

May Help Treat IBS

Research suggests senna is likely beneficial for treating certain gastrointestinal conditions, such as irritable bowel syndrome (IBS).

Senna's anti-inflammatory properties help relieve the digestive system from constipation and related symptoms, such as cramping and discomfort.

Some healthcare providers recommend senna as a complementary treatment for IBS-C, which is a type of IBS that includes constipation as a main symptom. More expansive research is still needed on senna's use as a remedy in IBS treatment.

Might Ease Hemorrhoid Symptoms

Supplementing with senna may help relieve uncomfortable symptoms of hemorrhoids (swollen veins around the anus), such as pain around the rectum.

Having constipation or hard stools can trigger or worsen hemorrhoids. Since senna can relieve constipation and soften stools, it may help manage hemorrhoid symptoms. Older research shows that senna has the potential to help heal hemorrhoids in some cases.

Additional studies around this theory are needed before senna can be broadly recommended as a specific hemorrhoid treatment.

Could Support Diabetes Treatment

In traditional medicinal practices, senna has been anecdotally used as a hypoglycemic treatment, meaning it may help lower blood sugar levels in people with diabetes.

A very small study had nine adults with diabetes and constipation consume senna tea with increasing consistency over several months. After treatment, the participants showed improvements in red blood cell glucose levels, constipation, and other diabetes-related complications.

While the findings are promising for long-term diabetes management, much larger studies are required to confirm them.

May Help Treat Obesity

Due to its stimulant and laxative properties, senna is often marketed as a diet or weight loss supplement in tea form. The herb triggers bowel movements, which can result in temporary water weight loss.

Researchers also theorize that senna might encourage toxin removal from the body, which supports metabolism and weight ma fnagement. However, further human clinical trials are needed before senna might be recommended as a tactic for treating obesity.

May Have Antibacterial and Antifungal Properties

Studies suggest that senna might be beneficial for combatting a variety of bacteria and fungal infections.

When applied topically, senna appears to have skin-healing properties—including fighting acne, clearing skin infections, and potentially treating inflammatory skin conditions like eczema.

Traditionally, cultures across the globe have utilized senna topical preparations for these purposes. Some current research supports these uses, but broader research is needed to confirm these potential benefits.

How To Take Senna

Senna is available in powder, capsule, and liquid form. It’s also common as a tea.

Some senna products come in capsules that you swallow whole with a glass of water; make sure to check the product label before consuming. Experts do not recommend chewing, splitting, or crushing these types of capsules.

Once you ingest senna, you can expect to notice results in about 6-12 hours. Some experts recommend taking the herb before going to bed so you can have a bowel movement in the morning.

Dosage

Dosing for senna can differ slightly based on the product and the person using the herb.

Most adults take around 17 milligrams (mg) of senna daily, in doses of once or twice daily, for no longer than 10 days. Talk to a healthcare provider before taking senna for more than a week.

Many senna supplement products contain 8-9 mg of senna per capsule.

Is Senna Safe?

When used as directed, senna is generally considered to be safe for adults and children ages 2 and older.

However, it may not be safe for people with certain health conditions, including:

• Crohn’s disease or ulcerative colitis, which are types of inflammatory bowel disease (IBD)
• Appendicitis, or inflammation of the appendix
• Heart disease
• Kidney disease
• Liver disease
• Dehydration

Talk to your healthcare provider about whether senna is right for you if you have one of the above conditions, are pregnant or breastfeeding, or are currently experiencing stomach pain or a bowel blockage.

Potential Drug Interactions

There is a potential for senna to interact with certain medications, such as: 

• Diuretics: Taking senna with diuretics (water pills) may cause potassium levels in the body to become imbalanced. Diuretics help excrete salt and water from the body. When paired with a laxative like senna, this effect could be doubled, removing too much potassium from the body.
• Estrogen: Senna may interfere with the absorption of estradiol, a form of estrogen found in some types of birth control. This could make the birth control less effective.
• Heart medications: As a stimulant laxative, senna can trigger low potassium levels, which could increase the risk of experiencing side effects with the heart medication Lanoxin (digoxin). Senna's laxative effect may also increase the blood-thinning effect of the medication Coumadin (warfarin) and increase bleeding risk.
• Stimulant laxatives: Taking senna while taking another form of stimulant laxative can compound the laxative effect, leading to dehydration and electrolyte imbalance.

Certain supplements, like horsetail and licorice root, may also interact with senna by increasing the chances of low potassium levels.

Some experts recommend taking senna supplements at least two hours before or after taking other oral medications. Check with your healthcare provider about the best way to take senna with your other medications or supplements.

What To Look For

Senna in supplement and tea form is widely available in drugstores and online.

When purchasing a senna product, check the label to see if the supplement has been tested by a third-party organization for purity and potency. The U.S. Food and Drug Administration (FDA) doesn't regulate supplements like it does medications. Organizations like U.S. Pharmacopeia, NSF International, and ConsumerLab offer quality testing that ensures the safety and effectiveness of the product.

Can You Take Too Much Senna?

It's not safe to use senna for a long period of time or take more than the recommended daily dosage as outlined by the supplement product or your healthcare provider.

If you take senna long-term, you could become dependent on the supplement for producing a bowel movement. Using senna for long periods or in high doses may also result in dangerously low potassium levels, liver toxicity, and other adverse effects.

Side Effects of Senna

When used as directed for a short period of time, the potential side effects of senna are usually mild. Some of the most commonly experienced side effects include:

• Stomach pain and cramping
• Diarrhea
• Nausea
• Bloating
• Vomiting
• Gas
• Urine discoloration

A serious side effect of using senna for a long period of time is liver damage, which could occur after using senna for several months. Though rare, electrolyte imbalances and changes in heart rhythm are also possible.

A Quick Review

Senna is an herb used medically to treat short-term constipation. It may also have other health benefits, such as pre-surgery bowel clearing, IBS symptom treatment, and hemorrhoid relief. Initial research suggests that senna may support the treatment of skin infections, diabetes, and obesity, though additional evidence is needed.

Senna may interact with certain medications, so consider speaking to a healthcare provider before adding this supplement to your daily regimen.