rubefacient
A substance for topical application that produces redness of the skin, e.g. by dilating the capillaries.
The symptoms had diminished for a time, under the employment of rubefacients and cathartics; but the pain in the left side of the thorax returned in the evening of the 29th.
Where it comes from
From Latin rubefaciens, present participle of rubefacere (“to make red”).
Adapted from the Wiktionary entry rubefacient (CC BY-SA 4.0).