An injectable heat generating biocompatible ceramic compositions based on hydraulic calcium aluminate, which can be used for therapeutic treatment in vivo, such as tumour treatment, pain control, vascular treatment, drug activation etc, when curing in situ, and which form a biocompatible solid material that can be left in the body for prolonged periods of time without causing negative health effects, and can also be used to restore the mechanical properties of the skeleton after cancerous diseases as well as in a medical implant, an orthopaedic implant, and a dental implant as a dental filling material.