comfrey (generic name)
an herbal product - treats Pain, Myalgia, and Inflammation
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TraditionWARNING: DISCLAIMER: The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.
Acne, aging, analgesic (pain reliever), anemia, angina (chest pain), antifungal, anti-inflammatory, antimicrobial, antioxidant, antipyretic (fever reducer), arthritis, broken bones, bronchitis, bruises, burns, cancer, conjunctivitis (pinkeye), cough, cough (bloody), dermatitis, diaper rash, diarrhea, expectorant (induces cough), eye infections (blepharitis), food uses, gangrene, gastritis, gout (foot inflammation), gum disease, gynecological disorders, hair tonic, hemorrhoids, hernia, high blood pressure, impetigo (pus-filled blisters), inflammatory bowel disease, lupus, mastitis (painful inflammation of breast), otitis (ear infection), pharyngitis, pleurisy (lung inflammation), rash, sexual arousal, sinusitis, skin disorders, sports injuries, sprains, thyroid disorders, tissue healing after surgery, ulcers, urine blood, uterine tonic, varicose veins, vasoprotective, wound healing.
Adults (18 years and older)
Due to safety concerns, taking comfrey by mouth is not recommended and oral sources cannot be sold in the United States. Traditional uses of comfrey include ingestion as an herbal tea. The 1990 German Commission E Monographs suggest maximal daily dose of 100 micrograms (external) unsaturated pyrrolidine alkaloids daily. The American Herbal Products Association's Botanical Safety Handbook from 1977 has similar recommendations.
Traditionally, a cloth or gauze soaked in an infusion (100 grams fresh, peeled root simmered in 250 milliliters water for 10-15 minutes) and applied to the skin several times daily has been used; duration was not noted. For a salve, olive oil and beeswax can be added and cooled.
Children (younger than 18 years)
There is no proven safe or effective dose for comfrey in children.
SafetyDISCLAIMER: Many complementary techniques are practiced by healthcare professionals with formal training, in accordance with the standards of national organizations. However, this is not universally the case, and adverse effects are possible. Due to limited research, in some cases only limited safety information is available.
Avoid in individuals with a known allergy or hypersensitivity to comfrey or its constituents.
Side Effects and Warnings
Comfrey is possibly safe when used as a cream applied to the skin for short-term (up to two weeks) treatment of minor injuries with no open wounds. Alkaloids may also be absorbed through intact skin, so precautions should still be taken. Use caution when using topical creams containing comfrey for extended periods.
Comfrey is likely unsafe when taken by mouth (orally) due to toxic pyrrolizidine alkaloids in comfrey. The U.S. Food and Drug Administration (FDA) has recommended removal of oral comfrey products from the market. Products made of comfrey root contain high levels of pyrrolizidine alkaloids.
Possible side effects associated with comfrey use include: abdominal pain, acute pneumonitis (inflammation of the lungs), ascites (accumulation of serous fluid in the abdominal cavity), Budd-Chiari syndrome (a rare liver disease in which a blood clot occurs in the large vein leading from the liver called the hepatic vein), cancer, damage to Disse's space, disruption of the sinusoidal wall, dose dependant liver damage, elevated serum transaminase levels, extravasation of red blood cells, heart problems, hemorrhagic necrosis, hepatic necrosis, hepatic veno-occlusive disease, hepatomegaly, jaundice, liver damage, liver failure, liver tumor induction, loss of definition of hepatocyte cellular membranes, loss of hepatocyte microvilli, loss of sinusoidal lining cells, obstructive ileus, occlusion of sub lobular veins, phytobezoar, platelets in areas of bleb formation around hepatocytes, severe portal hypertension, sinusoids filled with debris including cellular debris, hepatocyte organelles and red blood cells, skin redness, small venous radicles of the liver, swelling of hepatocytes, vascular congestion, venous endophlebitis, and zone 3 necrosis of hepatocytes.
Avoid oral comfrey due to hepatotoxic (liver damaging) and carcinogenic (cancer causing) pyrrolizidine alkaloids; oral use has caused death. Avoid topical comfrey in individuals with or at risk for hepatic disorders, cancer, or immune disorders due to potential for absorption of toxic compounds.
Use topical (applied to the skin) creams containing comfrey cautiously in patients using anti-inflammatory medications due to potential for additive effects.
Use cautiously in patients taking cytochrome P450 3A4-inducing agents, which may increase the conversion of compounds in comfrey to toxic metabolites.
Pregnancy and Breastfeeding
Avoid comfrey during pregnancy and breastfeeding as it may be hepatotoxic (liver damaging). Toxins from comfrey can be found in milk from grazing animals that have consumed comfrey. Thus it is likely that comfrey toxins would also be excreted in human breast milk.