“Coscoll”(Molopospermum peloponnesiacum (L.) Koch) whose stems are traditionally consumed raw in salads in Catalonia is associated in oral tradition with many virtues as digestive, purifying, exciting, antioxidant and hematocathartic activities. However, stem composition and biological activity had never been studied. Nutritive values of plant material were determined by official methods and constituents from essential oil of Molopospermum peloponnesiacum stems were characterized for the first time in this study. The main constituents were dillapiol (60.1%) and 3-carene (15.2%). Moreover, total polyphenol content using Folin-Ciocalteu method, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity were determined. Molopospermum peloponnesiacum stem total polyphenol content was 101.0 ± 10.0 mg/100 g fresh weight (Gallic Acid Equivalent) and DPPH radical scavenging activity, relatively high, was close from spinach one. Thus, these first results reveal the potential beneficial properties of this plant, in relation with its traditional use in Catalonia.