Three cases of d-penicillamine-induced skin lesions, two hemorrhagic and one elastosis perforans serpiginosa (EPS)—like, were examined with the electron microscope. In hemorrhagic lesions elastic fibers were diminished. In EPS lesions elastic fibers were remarkably increased in the papillary and reticular dermis. These appeared bramble bush—like with elastic fiber stains as described by Lund. Ultrastructurally, the bramble bush fibers consisted of near-normal core and abnormal coat which is medium electron—dense and lacks the alternating pattern of dense and light layers of the normal dermal elastic fibers. The “thorns” were formed as regular swellings of this coating material at regular intervals and at a right angle to the long axis of these fibers. In some fibers the coating material did not encircle the entire circumference of the core, suggesting that it was added upon the normal elastic fiber after the disease process began. Elastic fibers in the perforation canal through the epidermis were either intact bramble bush fiber or degeneration of it. Collagen fibers in both hemorrhagic and EPS lesions were poorly stained with routine electron microscopic stains. The most striking abnormality was an extreme variation of thickness of individual fibers ranging from 0.01 μm to 0.05 μm. Banding patterns and periodicity were normal. Subendothelial separation of vascular endothelial cells in small vessels and actual degeneration of subendothelial elastic fibers (internal elastic membrane) in larger vessels seem to be the basic defect in hemorrhagic lesions. Elastosis perforans serpiginosa seems to be a phenomenon caused by a variety of abnormal elastic fibers. Clearly, the ones in our case are completely different from idiopathic ones. It is assumed that any abnormal elastic fibers which elicit foreign body recognition by the host are commonly eliminated through this phenomenon.