We have recently shown in a series of papers1that alpha-dinitrophenol markedly augments metabolism in doses which are not demonstrably harmful. As this drug may have a number of important clinical applications, it seems desirable to present a summary report of its pharmacologic and therapeutic effects, and to point out certain potential dangers in, and limitations to, its use. During the World War, dinitrophenol was called to the attention of French physicians by cases of poisoning from it in munitions factories. Only incomplete investigations of the actions of the compound were made at that time, as judged by published reports. Recently, Magne, Mayer, Plantefol and others2have extended or completed work begun some years previously but reported simultaneously with our entirely independent studies. We are in general agreement with them as to the main pharmacologic actions of the drug. The experimental studies have been extended by us and