Hot/Cold and Inflammation

Are you supposed to apply hot or cold to an inflamed injury? The answer is both and oddly enough I think that this answer involves the science behind acupunture.

Inflammation is a cell and tissue response to insult and injury -- damaged cells release chemical signals that recruit help from neighboring and also from distant parts of the body. The signals and response result in dilation of local blood vessels, swelling, accumulation of white blood cells, warming of the injured tissue and pain, i.e. inflammation. This is a dramatic and potentially dangerous response for the body as a whole. If too much tissue is involved, the blood pressure plummets and lethal shock results. Some inflammation is needed for the body to protect itself and heal following an injury, but the response must be limited.

Inflammation spreads and is self-perpetuating -- inflamed cells tend to stimulate neighboring cells to participate in the inflammation. The body blocks this spreading cycle by a regional anti-inflammatory response. In essence local inflammation occurs in a region of tissue that is becoming less responsive to inflammatory signals -- sensations of pain as well as hot and cold that are interpreted in the brain as a result of nerve signals from distant tissues result in responses through the vagus nerve complex that result in the regional production of anti-inflammatory cytokines.


Application of hot or cold to an injured area results in a decrease in pain and inflammation. Initial application of cold is thought to slow the initial inflammation, but subsequently either hot or cold is anti-inflammatory. This appears to be a skin response that effects deeper tissues. Hot pepper products containing capsaicin (left) or cooling menthol (right) ointments work to reduce inflammation by stimulating the same receptor proteins for hot and cold. A convenient source of fast acting menthol is Vick's VapoRub. Oddly the unusual fatty acids (below) in castor oil also work by binding to the hot receptor.[figures from Wikipedia]

You can test the impact of castor oil by chewing a hot pepper, rinsing and drying your hot mouth and then rubbing your mouth with castor oil. The castor oil is related in structure to olive oil, so it has a similar taste. In about 30 seconds the castor oil penetrates the lining of your mouth and reaches the hot receptors already triggered by the hot pepper caspsaicin and the hot sensation dissipates.

You can also get pain relief by applying castor oil to hands and feet experiencing arthritic pain or tendonitis. Interestingly, with the regional response of the anti-inflammatory system, pain in a finger can be relieved by application of castor oil or menthol to the base of the finger or even around the wrist. Sweat bands or cotton gloves or socks can be used to prolong the treatment overnight and you will awaken with very soft skin [Most of the oil will be absorbed and the remainder is like a mild soap, so it is easily washed off the surface.] and relief from inflammation. Results may vary, but it can be very dramatic. Castor oil treatments seem to be very effective in reducing pain and inflammation. If it is helpful to you please let me know.

It is my observation that the placement of the castor oil can be used to mimic acupunture. If any readers have results to support or contradict this observation, please comment.