[Code of Federal Regulations] [Title 21, Volume 5] [Revised as of April 1, 2008] From the U.S. Government Printing Office via GPO Access [CITE: 21CFR347.12] [Page 275] TITLE 21--FOOD AND DRUGS CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF PART 347_SKIN PROTECTANT DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE--Table of Contents Subpart B_Active Ingredients Sec. 347.12 Astringent active ingredients. The active ingredient of the product consists of any one of the following within the specified concentration established for each ingredient: (a) Aluminum acetate, 0.13 to 0.5 percent (depending on the formulation and concentration of the marketed product, the manufacturer must provide adequate directions so that the resulting solution to be used by the consumer contains 0.13 to 0.5 percent aluminum acetate). (b) Aluminum sulfate, 46 to 63 percent (the concentration is based on the anhydrous equivalent). (c) Witch hazel.