IN human beings, eczematous dermatitis is possibly the most common of all recognized allergic diseases."1 It is an entity which may be caused by many unrelated substances. In our private practice Dr. Bedford Shelmire and I kept notes for a period of one year on all patients with contact dermatitis in whom the offending allergen or allergens were discovered. The purpose of this paper is to present the unusual features of a few of these cases, to point out the common sensitizing substances found to be peculiar to some specialized trades, and to emphasize the frequent occurrence of sensitization dermatitis from topical medications. All cases presented represent proved examples of eczematous contact dermatitis. In each case the opportunity for exposure to the substance or substances was demonstrated; an eczematous reaction followed patch tests with harmless concentrations of the material in question and elimination of