In a polymethyl methacrylate bone cement (A) comprising a liquid monomer component (B) and a solid component (C), (B) contains dye(s) (I) insoluble or sparingly soluble in methyl methacrylate and a synthetic, protein-free, hydrophobic, low-molecular or oligomeric solubilizer (II) for (I) in dissolved form, so that (B) is visibly clear at room temperature. (I) and (II) are also homogeneously dissolved in the polymethyl methacrylate or polymethyl acrylate of (C).
