The invention relates to porous bioglass and to the preparation method thereof. More specifically, the invention relates to a solid, porous crystalline or partially-crystalline composition containing at least SiO2, Ca O , Na2O, and P2O5, comprising micropores and macropores. The invention is characterised in that: the pore ratio varies between 50% and 80%, preferably between 60 and 75%, and is measured using the geometric method; the average diameter of the macropores varies between 100 and 1250 micrometers, preferably between 150 and 300 micrometers; the average diameter of the micropores is less than or equal to 5 micrometers; and the compression strength varies between 7 MPa and 70 MPa. The invention also relates to the method of preparing one such composition and to such a composition treated with a physiological liquid having an ionic composition similar to that of human plasma. The invention also relates to an implant which is made from one such composition.