The sea anemone Anemonia sulcata is the clinically most important Actinaria in the Adriatic Sea. Between 1965 and 1980, 55 patients stung by this cnidarian were seen at the Pula Medical Center in Istria, Yugoslavia. The majority of injuries were inflicted upon the upper extremities, chest, or abdomen. Pain and the appearance of small blanched papules surrounded by slightly reddened and edematous bases were the usually initiating manifestations. Linear lesions were sometimes seen. Vesicles, sometimes filled with serous fluid, localized discoloration, and the formation of bullae sometimes followed. Somnolence, dizziness, nausea, vomiting, muscle aches, and lid edema were reported in some cases. The treatment of these injuries in the northern Adriatic Sea and elsewhere is discussed.