Senna is an herb that comes from several different flowering species of the Cassia plants. The leaves, flowers, and fruits of the senna plant have been used in tea as a laxative or stimulant for centuries.
The leaves of the Senna plant are also used in some teas to help relieve constipation or promote weight loss.
The most common Cassia senna plants used are the C. acutifolia, and C. angustifolia plants, which are grown in the Middle East and India.
Senna is most often used as a laxative, either to relieve constipation or in some cases, to help with weight loss. It is also an ingredient in some conventional over-the-counter laxatives.
The United States Food and Drug Administration (FDA) have approved senna as a non-prescription drug to treat constipation. The most common doses are:
- Children: 8.5 milligrams (mg) per day to cause a single bowel movement
- Children over 12 and adults: 17.2 mg per day, with no more than 34.4 mg each day
- Older adults: 17 mg per day
- Postpartum pregnancy: 28 mg per day, divided into two doses
It is not recommended to use senna for longer than 2 weeks at a time.
There have been some case reports of people suffering from liver damage, coma or nerve damage after using senna. In these cases, people were using senna at much higher than the recommended doses and for more extended periods of time.
People with certain medical conditions should not use senna, including:
Also, anyone with abdominal pain or children under the age of 2 years should not use senna.
Pregnant women and breast-feeding mothers
Senna may or may not be safe for use during pregnancy. Pregnant women with constipation should speak with their doctor before using senna or any other laxative.
Senna appears to be safe for women who are breast-feeding, when used in the recommended amount. Even though a small amount of the herb passes into the breast milk, it does not appear to have any effect on a nursing baby’s stool.
Senna can cause some uncomfortable and even some serious side effects.
They can include:
- fluid loss
- abdominal pain
- electrolyte disturbances
- feeling faint
Long-term use of senna can cause dependence in order to have a bowel movement, finger clubbing (usually reversible), rectal bleeding, and wasting.
Someone experiencing any of these side effects should speak with their doctor, especially if they do not go away.
It is essential to drink plenty of fluids or electrolyte replacement solutions, such as Gatorade, when taking senna. This is to prevent a person from losing too much fluid or electrolytes, especially if they have diarrhea.
To deal with cramping or abdominal pain, people can reduce the dose until the discomfort subsides.
There are several drug interactions to be noted. By being aware of these, people can make sure that they are drinking senna tea safely.
People taking the following medications or herbal supplements should avoid taking senna:
- Contraceptives: Senna can interact with the form of estrogen in some contraceptives, including the vaginal ring, patch or pills. It might make the birth control less effective, making it more likely for an accidental pregnancy to occur.
- Digoxin: Senna can cause electrolyte imbalances in the body, especially in potassium levels. Low potassium can cause problems for someone taking digoxin.
- Warfarin: Diarrhea in people taking warfarin can increase the risk of serious bleeding. Because senna can cause diarrhea, anyone taking warfarin should avoid using senna.
- Diuretics: Like senna, some diuretics can also decrease potassium and other electrolyte levels. Taking these two medications together can cause potassium levels to drop to a dangerous level.
- Estrogens: Estrogens in hormone replacement therapies react the same way as birth control pills. Using senna with hormone replacement therapy may mean that the estrogen is not absorbed or work as well.
- Horsetail: Horsetail is an herb that some people take for several different reasons. There is some thought that horsetail could lower potassium levels in some people. Taking senna with horsetail may lower potassium levels too much.
- Licorice: Licorice also lowers potassium levels; people should avoid taking both licorice and senna together.
Senna is generally well tolerated and thought to be safe for most people. However, it does have the potential to cause serious complications in some people with certain health conditions and who take certain medications.
It is best to consult a doctor with any questions about taking senna.