The present invention provides a kit based on two pastes that is designed to produce bone cement with high initial stability and therefore low post-cure. Said kit comprises a paste A and a paste B, whereby (a) paste A contains (a1) a polymerisable monomer with a pH in water in the range of 5 - 9, (a2) a filling agent that is insoluble in (a1), and (a3) a barbituric acid derivative selected from the group consisting of 1,5-disubstituted barbiturates, 1,3,5-trisubstituted barbiturates, and 1,3,5- tetrasubstituted barbiturates, and (b) paste B contains (b1) a polymerisable monomer with a pH in water in the range of 5 - 9, (b2) a filling agent that is insoluble in (b1), (b3) a peroxide that is soluble in (b1), (b4) a heavy metal compound that is insoluble in (b1) and selected from the consisting of heavy metal salts and heavy metal complexes, whereby at least one of the pastes A and B contains a halide salt.
