INTRODUCTION It is our desire and purpose to report a case of pityriasis rubra pilaris (Devergie) apparently cured by the internal administration of thyroid substance. Thyroid substance has been advocated therapeutically in this disease by several authorities; therefore when the patient, whose history is reported, appeared for treatment, it was decided to employ organotherapy in view of certain minor signs of dysthyroidism. With the exception of a 2 per cent. salicylic acid ointment used at the onset for a period of two days, no further measures, either general or local, were employed. We are further emboldened to report this case by reason of the rapid involution occurring, soon after the glandular medication was begun, in a disease generally regarded as pursuing a protracted clinical course and as being unusually resistant to all forms of treatment, either internal or local. REPORT OF CASE History.— B. B., a white man, married, aged