Are green clay cataplasms effective to treat tendinitis?

Question

I have heard and read from various (low quality) sources that green clay cataplasms are effective to treat tendinitis (a.k.a. tendonitis). E.g.:

• Argiletz:

  Green clay can be used for healing bruises and relieving pain in children and grown-ups: rheumatism, sustained effort, long walks (soothes sore feet), tendinitis, back pain...

• Hope For Health:

  Pain Relief, Anti-Inflammatory Action, and Swelling Reduction. Helpful For tendinitis.

• Hawaii Naturopathic Retreat:

  Tendonitis

  Clay wrap around entire area if possible, 1/4 – 1/2 inch thick, covered, for 20 minutes to an hour initially, increased to overnight applications as tolerance permits, for three days to three weeks.

Are there any studies on green clay cataplasms' effectiveness to treat tendinitis?

I am aware of the existence of question Does eating clay have any beneficial effect?, but I'm interested in the external use of green clay, not internal.

Answer 1

There are no studies on PubMed with the terms "clay, poultice and tendintis/tendonitis" so we can conclude that there has been no peer reviewed published research in this area to support the claims.

Medline Plus advises on the management of tendinitis [1]

Rest or immobilization of the affected tendons is helpful for recovery. This may be achieved using a splint or a removable brace. The application of heat or cold to the affected area can help.

So, if the green clay poultice provides immobilization with some heat, it might conceivably help.

[1] http://www.nlm.nih.gov/medlineplus/ency/article/001229.htm