Introduction:

Comfrey is a plant. Even though this plant contains poisonous chemicals called pyrrolizidine alkaloids (PAs).  Comfrey is used as a tea for upset stomach, ulcers, heavy menstrual periods, diarrhea, bloody urine, persistent cough, painful breathing such as pleuritis, bronchitis, cancer, and chest pain (angina). It is also used as a gargle for gum disease and sore throat.

Mode of action:

The chemicals in comfrey might have a healing effect and reduce inflammation when applied to the skin. However, comfrey contains toxic chemicals that can be absorbed through the skin.

Uses and effectiveness:

• Back pain. Applying a specific comfrey extract to the affected area for 5 days seems to decrease lower or upper back pain.
• Osteoarthritis. Applying a specific comfrey extract  to the affected area for 3 weeks or applying a specific cream containing comfrey extract, tannic acid, Aloe vera gel, eucalyptus oil, and frankincense oil  to the affected are for 12 weeks seems to decrease pain in people with knee osteoarthritis.
• Sprains. Early research suggests that applying comfrey ointment to the affected area for up to 2 weeks improves mobility, decreases pain, and reduces tenderness and swelling of sprains. The effect of comfrey ointment in relieving pain and reducing swelling seems to be comparable to the effects of diclofenac gel.

May also be effective in:

• Bruises.
• Skin ulcers.
• Wounds.
• Broken bones.
• Heavy menstrual periods.
• Diarrhea.
• Cough.
• Sore throat.
• Gum disease.
• Joint pain.
• Chest pain.
• Cancer.
• Inflammation

Special precaution:

Pregnancy and breast-feeding: Comfrey is likely unsafe to take by mouth or apply to the skin if you are pregnant or breast-feeding. In addition to causing liver damage and possibly cancer, the PAs in comfrey might also cause birth defects. Even topical use is unwise, since the PAs can be absorbed through the skin.

Broken or damaged skin: Don’t apply comfrey to broken or damaged skin. Doing so might expose you to large amounts of the chemicals in comfrey that can cause liver damage and other serious health effects.

Liver disease: There is a concern that comfrey might make liver disease worse. Don’t use comfrey if you have any problems with your liver.

Conclusion:

Modern scientific studies have found some evidence to support comfrey’s use in treating minor wounds and joint pain, but oral preparations of the plant have also been linked to liver damage and cancer. You should never take comfrey by mouth. You should also avoid using it on open wounds.  Comfrey may be safe to apply to your skin or closed wounds for short periods. Always talk to your doctor before using products that contain it. It is best avoided especially if you are:

• a child
• an older adult
• pregnant
• breast-feeding
• someone with a history of liver disease