Comfrey (Symphytum officinale) has been used for centuries in herbal medicine, but its use comes with significant safety concerns. The primary concern is the presence of pyrrolizidine alkaloids (PAs), which can cause severe liver damage and are potentially carcinogenic. (Searched 4 sites)

Safe Uses of Comfrey

Topical Applications:

Wound Healing and Skin Conditions: Comfrey can be used safely on unbroken skin for treating wounds, bruises, sprains, and other minor injuries. It is often used in the form of poultices, salves, and ointments. However, it should not be applied to broken skin or used for more than 10 days in a row to avoid absorption of harmful PAs (Drugs.com) (SPICEography) .

Gardening:

Fertilizer: Comfrey leaves are rich in nutrients like nitrogen, phosphorus, and potassium, making them excellent for use as a natural fertilizer. The leaves can be steeped in water to create a liquid fertilizer or added directly to compost (Common Sense Home).

Unsafe Uses of Comfrey

Internal Use:

Ingesting Comfrey: Consuming comfrey, whether as a tea, in salads, or in other foods, is generally considered unsafe due to the risk of liver damage and other serious health issues. The PAs present in comfrey can accumulate in the liver and cause veno-occlusive disease, leading to liver failure and potentially cancer (Drugs.com) (SPICEography) .

Conclusion

While comfrey can be beneficial for certain topical applications and in gardening, it is not safe for internal consumption due to the high risk of liver toxicity and other serious health problems. It is always best to consult with a healthcare provider before using comfrey, especially if you have underlying health conditions or are taking other medications.