The present invention relates to a method for growing, rapidly and massively ex vivo, cells collected from a living subject to provide a safe and effective pharmaceutical preparation for biological tissue repair/regeneration. Specifically, the present invention relates to a method for growing cells in a sample collected from a living subject by culturing the cells in a medium containing allogeneic (including autogenic) serum. Preferably the allogeneic serum has been determined as being negative for a serum tumor marker and/or an infectious factors, and the amount of the anticoagulant (e.g., heparin, a heparin derivative, or a salt thereof) added to the collected sample is less than 5 U/mL with respect to the volume of the sample or the amount of the anticoagulant in the medium at the start of culture is less than 0.5 U/mL. The present invention further relates to use of the method.