Tar-water is a Medieval medicine consisting of pine tar and water. It was foul tasting and so slowly dropped in popularity, but was revived in the Victorian era.
The use of the medicine is mentioned in Great Expectations, Chapter 2 by Charles Dickens. Young Pip and his brother in law Joe were often force fed it by Mrs. Joe, Pip's elder sister, whether they were ill or not, as sort of cruel punishment.
The physician Cadwallader Colden extolled the virtues of pine resin steeped in water. This concotion also was called "Tar water"[1].
The philosopher George Berkeley also lauded tar water in his tract Siris.