A bolt with an external thread and a cylindrical bolt shank made of allogeneic, cortical bone material for surgically operative osteosynthesis, wherein the external thread concerns a symmetrical angular or trapezoidal thread which has at least one thread turn per millimeter, and the bone material is formed by osteons (5) and is permeated by Haversian canals (6). According to the invention, it is proposed that the thread flanks (9a, 9b), delimiting a thread groove of the angular or trapezoidal thread merge into one another via a thread root portion (8) whose length, in an axial section of the bolt, is in the range of 0.02 mm to 0.6 mm. In this way, it is possible to produce bone screws (1) with increased strength, such that less suitable donor material can also be used for the production of high-quality bone screws (1).