Educational reference — not medical advice. Talk to a clinician before changing what you take.Read more.

Remedy · herb

Comfrey (topical)

Also: Symphytum officinale, knitbone

A traditional "knitbone" applied to the skin for back pain and sprains — for topical use only.

Active compounds Allantoin

Evidence by condition

Each grade reflects the research for Comfrey (topical) and that condition specifically.

  • B
    Low back pain

    Topical comfrey root extract reduces acute back pain and improves mobility vs placebo, comparably to topical diclofenac.

    2 citation s
  • B
    Knee osteoarthritis

    Topical comfrey ointment markedly reduced knee OA pain versus placebo in randomized trials.

    2 citation s

Never take comfrey by mouth: it contains pyrrolizidine alkaloids that can severely damage the liver. Use only labelled PA-free topical products on intact skin, short-term.