Comfrey - Symphytum officinalis (in the Boraginaceae or Borage family)
Parts used: Root and main rib of leaf have the most mucilage and allantoin.
Taste/Smell: Mucilaginous, nutritious tasting, bland.
Tendencies: Cooling and moistening.
Dosage: Used externally as a poultice, paste, or fomentation.
Use: Externally: (a) Contusions, (b) Sprains, (c) Dislocations, (e) Wounds, (f) Burns, (g) Ulcers, (h) All inflammatory skin disorders.
Comfrey's demulcent and anti-inflammatory effects have been used historically as an internal agent for soothing mucous membrane irritation in the gastrointestinal tract, respiratory tract and urinary tract. It acts as an anti-inflammatory when there is damage to the periosteum, promotes callus formation in fractures and decreases inflammation of tendon sheaths. It has been used for arthritis, dislocations, contusions, hematomas, thrombophlebitis, phlebitis, parotitis, and glandular swellings. Comfrey can also be used as a gargle in periodontitis and pharyngitis. But internal use is no longer advised due to the possibility of pyrrolizidine alkaloid poisoning inducing veno-hepato-occlusive disease.
Externally it decreases the healing time for skin wounds and irritations and has been shown to act as a mild analgesic.
Comfrey contains 6-8% allantoin, 0.02-0.07% pyrrolizidine alkaloids, 4-6% tannins, intermedine, aetylintermedine, lycopsamine, acetyllycopsamine, symphytine, mucilage, starch, triterpenes like isobauerenol and sterols like sitosterol. The constituent, allantoin, promotes cell proliferation and is thought to be the main reason for its healing action.
Contraindications: Do not use internally due to possible pyrrolizidine poisoning causing veno-occlusive disease and carcinogenic activity. It is also contraindicated in pregnancy and nursing mothers.