Biocompatible and resorbable melt derived glass compositions which include: SiO2 60-70 weight-%, Na2O 5-20 weight-%, CaO 5-25 weight-%, MgO 0-10 weight-%, P2O5 0.5-3.0 weight-%, B2O3 0-15 weight-%, Al2O3 0-5 weight-%, and which contain less than 0.05 weight-% potassium. Biocompatible and resorbable glass fibres manufactured from these glass compositions, medical devices containing fibres of the invention, the use of these compositions for the manufacture of glass fibre and the use of the fibres for the manufacture of medical devices are also disclosed.
