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Senna Does Have Side Effects, it's Not As Harmless As it Seems

Senna Side Effects
Senna alexandrina belong to Senna, which is a large genus of flowering plants. Anthraquinone derivatives or glycosides present in this species are responsible for the laxative effects of this herb. This HolisticZine write-up provides information on the side effects of Senna.
Lalan Maliakal
Last Updated: May 31, 2018
It is often assumed that herbs are not likely to cause any harm to our body. This is certainly a misconception. Herbs can cause adverse effects in the event of an overdose. Also, some herbs could cause adverse effects in individuals affected by certain medical conditions. Thus, it is essential to consult a herbal practitioner before you start taking herbs. Senna is a herb that is commonly used by individuals affected by constipation.
Senna is a genus of large flowering plants that comprises more than 300 species. It is also called Cassia senna, India senna, Alexandrian senna, and Khartoum senna. It is a member of the bean family, and is native to China, India, and Pakistan. For centuries, the leaves and seeds of senna have been harvested for their therapeutic properties by various cultures. Compounds called anthraquinones which are present in the leaves and pods of senna, are extremely potent laxatives. Since senna fruit is believed to be gentler than the leaves, the American Herbal Products Association (AHPA) recommends the labeling of products made from the leaves, and has warned against the long-term use of senna leaf. This herb is also available over the counter in the form of capsules, tablets, liquid extract, and dried root.
Side Effects
Senna is an FDA-approved non-prescription drug. It can be taken by adults and children aged 12 and above for the treatment of constipation. Some brands offer 8.5 mg and 17.2 mg tablets. The usual daily dose for adults is 17.2 mg. It's advisable not to take more than 34.4 mg per day. In case of children, a daily dose of around 8.5 mg has been observed to cause a bowel movement daily. A daily dose of 17 mg is suggested for treating constipation in elderly people. It must be noted that senna is a stimulant laxative. It is considered to be safe during pregnancy and breastfeeding when taken by mouth for a short period. However, it is advisable to use it only after consulting with your healthcare provider. If women experience constipation following pregnancy, they could take 28 mg in 2 divided doses. Safety concerns have been raised regarding the long-term use of this herb, or administration of high doses. Laxative dependence and hepatotoxicity (liver injury or damage) has been linked to the frequent or long-term use, or use of high doses.
Some of the common side effects of senna are:
  • Abdominal pain
  • Diarrhea
  • Bloating
  • Excessive gas
  • Rectal irritation
  • Change in the color of urine
  • Nausea
Medical help must be sought, if these side effects persist, and one experiences the following side effects:
  • Rectal bleeding
  • Rapid heart rate
  • Sweating
  • Fainting
  • Skin rash
  • Constipation
Senna is recommended to be used only for 7-10 consecutive days. Prolonged use may develop into dependency on senna for normal bowel movements. This condition is known as the 'lazy bowel syndrome', which means you would be unable to evacuate your bowels without stimulants. Senna use, if continued for longer period of time, may result in dehydration, worsened constipation, pigmentation of the colon, and enlargement of the ends of fingers and toes. In addition, prolonged use could cause osteomalacia, weakening and softening of the bones, and arthropathy, a type of progressive joint disease. It is also known to disturb the balance of electrolytes, by decreasing the levels of potassium. The long-term use of this herb could give rise to symptoms such as weight loss, muscle wasting, fatigue, and weakness that could be associated to a disorder called cachexia. Studies have revealed that the long-term use of anthraquinone could put one at a risk of developing adenomas and cancer. An overdose could also cause bloody diarrhea and vomiting.
The use of senna is not recommended for children below 12 years of age. People with chronic gastrointestinal problems like Crohn's disease, ulcerative colitis, hemorrhoids, or appendicitis should not use it. If you have a medical history of allergies, consult your doctor before taking it. Also, this herb could interact with drugs such as birth control pills, digoxin, estrogens, warfarin, water pills, etc., or herbs such as horsetail, licorice, and other stimulant laxative herbs. So, do inform your healthcare provider or herbal practitioner about preexisting medical conditions or other drugs that you are taking currently.
Cases Reported
  • In a 2005 report published in the Annals of Pharmacotherapy, a 52-year-old woman developed acute liver failure and kidney impairment after ingesting one liter of senna tea every day for over three years.
  • In Guyana, two girls aged 3 and 5 died in 2009, after consuming senna pod tea in combination with an antidiarrheal medicine called Lomotil and bush tea. Their death appeared to be caused due to electrolyte imbalance and acute dehydration due to senna overdose in combination with the use of the antidiarrheal drug.
  • Senna-induced hepatitis was reported to have developed in an elderly patient who took it to cure chronic constipation.
On a concluding note, exercise caution while using herbs or herbal supplements. In case of senna, an overdose or use for extended periods could cause adverse effects that could turn out to be life-threatening in nature. So, consult your healthcare provider before you start taking this laxative.
Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.