A rubefacient's a substance for external application that produces redness of the skin for example by causing dilation of the capillaries and an increase in blood circulation. They're believed to relieve pain by a counterirritant effect, and many act via transient receptor potential ion channels. Common medicinal rubefacients include : Capsaicin (derived from Cayenne, Capsicum minimum) Salicylates (such as Oil of Wintergreen, Methyl Salicylate) Nicotinate esters Rubbing alcohol Common herbal… (More on Rubefacient)