What is it?
Rhubarb acts as a stimulant laxative, but has not been shown to treat or prevent cancer.
Rhubarb is a perennial herb, and the stalks are sometimes consumed as food. In Traditional Chinese Medicine (TCM), the rhizome and root are use to treat gastrointestinal and liver diseases. It is also used in herbal formulas such as Ma Zi Ren Wan. In lab animals, compounds in rhubarb called anthraquinones reduced pain, inflammation, and some tumors.
Studies in humans are limited, but suggest rhubarb can improve feeding tolerance and relieve gastrointestinal dysfunction in very ill patients. It may also reduce excess blood levels of pancreatic enzymes and pancreatitis events caused by some procedures. Other initial studies suggest it can treat mouth sores or help reduce radiation side effects. Additional studies are needed to determine safety and effectiveness.
Rhubarb is considered to be a stimulant laxative. It is also a component of Essiac tea. Patients and physicians should be aware of the potential for additive effects.
What are the potential uses and benefits?
- To reduce cancer treatment side effects
One study suggests that a rhubarb extract may reduce side effects from radiation therapy in lung cancer patients. Additional studies are needed. - To relieve constipation
Rhubarb acts as a laxative, although clinical trials have not tested this use. - As a fever reducer
There is no scientific evidence to support this claim. - To suppress the immune system
Lab data show that rhubarb decreases the activity of isolated immune cells. - To reduce inflammation
Some studies suggest that rhubarb has anti-inflammatory effects. - To treat infections
There is no scientific evidence to support this claim. - To treat ulcers
A small study suggests rhubarb may be useful for treating oral ulcers. More studies are needed.
What are the side effects?
Case reports
- Kidney damage/failure: In a type-1 diabetic patient with normal kidney function following excess ingestion of rhubarb and in a 75-year-old man from excess intakes of rhubarb stew over a few weeks.
- Dark pigment deposits in the colon: In a 67-year-old woman with long-term use of a natural fiber supplement containing rhubarb. This condition is often associated with chronic laxative use. It was reversed after a long period of product discontinuation and repeat colonoscopy.
What else do I need to know?
Do Not Take if:
- You are taking CYP450 substrate drugs: Rhubarb may reduce the effectiveness of these drugs, but clinical significance has yet to be determined.
- You are taking digoxin: Potassium loss due to the laxative effect of rhubarb means it may increase the risk of low potassium levels.
- You are taking melatonin: Lab studies suggest that using both products together may affect the way melatonin is metabolized, but clinical relevance is not yet known.
- You are taking cyclosporine: In lab studies, rhubarb decreased cyclosporine bioavailability. Clinical relevance is not yet known.
- You are taking methotrexate: In lab studies, rhubarb increased exposure to methotrexate. However, clinical relevance is not clear.
- You have kidney disease: Rhubarb is high in oxalates and may cause kidney problems in some individuals.
Special Point:
- Rhubarb is high in oxalates, and may cause kidney problems in some individuals.
- Animal studies suggest the potential for liver toxicity at high doses and with long-term use.