There not enough scientific supporting evidence to support the claims that cream of tartar works for acne. 

More Info: Though there is little scientific evidence to support the ingestion of cream of tartar as an effective treatment for acne, there are plenty of alternative health enthusiasts who follow this old folk remedy and swear by it.  Take a stroll through the annals of history to explore how cream of tartar has been used medicinally through the centuries.

Cream of Tartar Is an Old Folk Remedy

Dickens Press is republishing fascinating historical health and beauty techniques dating back to the 1900's and before. The book The Ladies' Beauty Book And The Old Home Doctor - Containing Over 1300 Toilet Receipts And Hints To Assist In Improving One's Personal Appearance by William H. Keppel mentions the use of cream of tartar as an acne treatment. 

The book notes that though the thought of the day was to blame the appearance of pimples on "even the slightest hygienic error", they were actually a result of dyspepsia-or upset stomach.  In this case the simple pimple treatment was to relieve the dyspepsia through various home remedies one of which included cream of tartar.  Here is the recipe:

"Take teaspoonful doses every evening of equal parts of flowers of sulphur and cream of tartar mixed into a paste with molasses or honey, and continue it for a week or two..."

Other Old-Home Remedies for Cream of Tartar

Diuretic: Cream of tartar mixed with water is said to be a diuretic, and helps to remove albumin from the urine.

• Tyler, Varro E. Hoosier Home Remedies . S.l.: Purdue Univ Press, Print.

Hives: Add a few drops of water to cream of tartar to form a paste. Spreading it on hives will relieve the itch.

• Hoffman, Matthew, and Eric Metcalf. 1,801 home remedies: trustworthy treatments for everyday health problems. Pleasantville, N.Y.: Reader's Digest, 2004. Print.

Remedy for Dropsy: This old remedy does not instruct on how to take it, but insists the cream of tartar has a medicinal value as a cathartic and as such will help to eliminate swelling of soft tissue due to excess water.

• John Nelson Goltra. Preventative Medicine at Home New York and Chicago: Thomlinson-Humes, Inc. 1912 Print.

Venereal Disease: "Cream of tartar is apt to prove useful in the treatment of gonorrhea and venereal sores by reason of its absorbent and antiseptic properties."

• Dr. E. Oteri; "Therapeutic Breveties." The Medical Age 12 (1894): 186. Print.