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Comfrey
Comfrey — lo que la monografía europea realmente respalda, para qué no es, la forma y cuánto tiempo está pensado usarse, efectos adversos y la 1 interacción medicamentosa documentada.
Esta es una página de referencia, no un diagnóstico ni una receta. Los productos herbales son farmacología real: tienen efectos, efectos adversos e interacciones. Diga a su médico y farmacéutico todo lo que toma, incluidos tés y suplementos, y nunca suspenda ni cambie un medicamento recetado por algo que lea aquí.
Qué es
Symphytum officinale L. — root and leaf
Nombres locales en la región que sirve este sitio:varemerohi (ET) · rohtoraunioyrtti (FI) · окопник (RU).
Agrupado aquí bajo Where the harm is. Posición regulatoria:External use only, with limits; oral preparations are not acceptable in the EU.
Lo que respalda la evidencia
La indicación registrada:External use on unbroken skin for bruises, sprains and strains, in pyrrolizidine-alkaloid-depleted preparations.
Comfrey is the clearest case of a traditional remedy that modern chemistry ruled out for internal use. It contains pyrrolizidine alkaloids, which the liver converts into reactive compounds that damage the small hepatic veins and cause hepatic veno-occlusive disease (sinusoidal obstruction syndrome); they are also genotoxic and carcinogenic in animal studies. Oral comfrey preparations were withdrawn in Europe decades ago on that basis. Externally, comfrey creams and ointments for bruises and sprains remain in use and have reasonable trial support for pain relief, but regulators restrict them to alkaloid-depleted preparations, intact skin only, and a limited number of days of use per year — because pyrrolizidine alkaloids are absorbed through skin. The wider lesson is that this is not a comfrey-only problem: the same alkaloids occur in ragwort, borage, butterbur and coltsfoot, and they contaminate herbal teas and honey when alkaloid-containing weeds are harvested with the crop. European food law sets maximum levels for pyrrolizidine alkaloids in herbal teas, teas, certain herbs and food supplements for exactly that reason.
D — Popular claim unsupported, or safety dominates The better trials are negative, or the substance appears in the literature mainly for the harm it has caused.
Para qué no es
Swallowing, in any form, including comfrey tea and "knitbone" infusions. Also not for open wounds, broken skin or grazes.
Forma, potencia y cuánto tiempo
Creams, ointments and gels of alkaloid-depleted root or leaf extract, for external use on unbroken skin.
Duración.Limited courses, and a limited total number of days per year — the restriction is on cumulative exposure, not on any single application.
Ninguna cifra en gramos aparece en esta página a propósito. La parte de la planta, el disolvente de extracción y la relación droga-extracto definen juntos una preparación, y un número tomado de una no describe otra. El razonamiento está en el hub; la cantidad que le aplica es la impresa en el envase que sostiene, y un farmacéutico la leerá con usted.
Efectos adversos
Externally, occasional skin irritation and contact allergy. Internally, liver injury that can be severe and irreversible.
Quién debería evitarlo
Never in pregnancy or while breastfeeding. Not on children. Not with existing liver disease.
Interacciones con medicamentos
| Medicamento o sustancia | Qué se describe |
|---|---|
| Anything else that stresses the liver | Anything else that burdens the liver — alcohol, other pyrrolizidine-containing plants, medicines with a hepatic signal — adds to the same target organ. |
La vista inversa — empezar por el medicamento en vez de la planta — está en la referencia de interacciones de medicamentos, alimentos y alcohol, y resumido para cada hierba de este sitio.
Fuentes:European Medicines Agency — Committee on Herbal Medicinal Products (HMPC), European Union herbal monographs · LiverTox: Clinical and Research Information on Drug-Induced Liver Injury (NIDDK, National Institutes of Health)· comprobado2026-09-06
Preguntas frecuentes
¿Para qué se usa comfrey?
External use on unbroken skin for bruises, sprains and strains, in pyrrolizidine-alkaloid-depleted preparations. Comfrey is the clearest case of a traditional remedy that modern chemistry ruled out for internal use. It contains pyrrolizidine alkaloids, which the liver converts into reactive compounds that damage the small hepatic veins and cause hepatic veno-occlusive disease (sinusoidal obstruction syndrome); they are also genotoxic and carcinogenic in animal studies. Oral comfrey preparations were withdrawn in Europe decades ago on that basis. Externally, comfrey creams and ointments for bruises and sprains remain in use and have reasonable trial support for pain relief, but regulators restrict them to alkaloid-depleted preparations, intact skin only, and a limited number of days of use per year — because pyrrolizidine alkaloids are absorbed through skin. The wider lesson is that this is not a comfrey-only problem: the same alkaloids occur in ragwort, borage, butterbur and coltsfoot, and they contaminate herbal teas and honey when alkaloid-containing weeds are harvested with the crop. European food law sets maximum levels for pyrrolizidine alkaloids in herbal teas, teas, certain herbs and food supplements for exactly that reason.
¿Funciona comfrey?
Valorado aquí D: The better trials are negative, or the substance appears in the literature mainly for the harm it has caused. Swallowing, in any form, including comfrey tea and "knitbone" infusions. Also not for open wounds, broken skin or grazes.
¿Cuánto comfrey debo tomar?
Esta referencia no imprime cifras en gramos, porque no se transfieren entre preparaciones de distinta fuerza de extracto. Lo que se puede decir con honestidad es la forma y la duración:Creams, ointments and gels of alkaloid-depleted root or leaf extract, for external use on unbroken skin. Limited courses, and a limited total number of days per year — the restriction is on cumulative exposure, not on any single application.
¿Cuáles son los efectos adversos de comfrey?
Externally, occasional skin irritation and contact allergy. Internally, liver injury that can be severe and irreversible.
¿Interactúa comfrey con medicamentos?
Sí — documentado paraLiver load. Cada una se describe en esta página, con un enlace a la referencia del lado medicamento donde exista.
Otros enwhere the harm is
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