[Code of Federal Regulations] [Title 21, Volume 4] [Revised as of April 1, 2008] From the U.S. Government Printing Office via GPO Access [CITE: 21CFR250.105] [Page 178] TITLE 21--FOOD AND DRUGS CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) PART 250_SPECIAL REQUIREMENTS FOR SPECIFIC HUMAN DRUGS--Table of Contents Subpart B_New Drug or Prescription Status of Specific Drugs Sec. 250.105 Gelsemium-containing preparations regarded as prescription drugs. It is the consensus of informed medical opinion that the margin of safety between the therapeutic and toxic concentration of gelsemium is narrow and it is difficult to predict the point at which the dose will be toxic. Very small doses may cause toxic symptoms. It is therefore the view of the Food and Drug Administration that gelsemium is not a proper ingredient in any product that is to be sold without prescription. Accordingly, any drug containing gelsemium will be regarded as misbranded under section 503(b)(4) of the Federal Food, Drug, and Cosmetic Act if its label fails to bear in a prominent and conspicuous fashion the statement ``Rx only.'' [40 FR 14033, Mar. 27, 1975, as amended at 67 FR 4906, Feb. 1, 2002]