The present invention relates to a connection system for components through which fluid flows in medicine and medical equipment, comprising a male connection cone (6, 30) and a threaded nut (7) least partially surrounding the connection cone (6) and having an internal thread (9), for captively connecting the male connection cone (6, 30) to a female receptacle of an additional component through which fluid flows. The invention is characterised in that the threaded nut (7) has radially circumferential through-holes (10) at least in some sections in the axial section of the circumferential jacket of the threaded nut and webs (11, 11′) are formed adjacent to the through-holes in the circumferential jacket, sections of the internal thread (9) being arranged on the inside of said webs in relation to the circumferential jacket. Furthermore, the invention also relates to the production of the connection system and to its use.