Demethylchlortetracycline (Declomycin) is a new antibiotic which has been produced by a mutant strain of Streptomyces aureofaciens. This is the parent organism of chlortetracycline. It differs from the latter by the absence of a methyl group in the 6-position on the basic tetracycline molecule. This compound has been given to animals to determine its toxicity and other animal screening procedures. It has shown a very low order of toxicity.1The drug is readily absorbed from the gastrointestinal tract and slowly excreted through the urine. This2property of being well absorbed from the gastrointestinal tract and producing much higher and prolonged serum antibiotic concentration after oral administration than either chlortetracycline or oxytetracycline makes it a useful drug in the treatment of acne vulgaris, acne rosacea, chronic folliculitis, and other pyogenic conditions caused by organisms sensitive to the tetracyclines. We employed the suggested dose schedule, 300 mg. initially followed by