A panacea is basically a cure-all. Most patent medicines of the 1800s were panaceas of one sort or another. Brown’s Household Panacea, sold during the late 1800s to the early 1900s for 25 cents a bottle, was advertised as a “family liniment” which was, oddly, also recommended for internal use.
Its advertising claimed it would treat any pain whether applied externally to the skin or taken by mouth:
For Internal And External Pains, Rheumatism, Pain in Stomach, Bowels or Side, Colic Diarrhoea, Colds, Sprains, Burns, Scalds, Cramps & Bruises.
Its ingredients, like most patent medicines of the day, were kept secret and I was unable to find any contemporary analysis of the contents.