The present invention concerns a method for the determination of apoptotic products in samples taken from patients in which apoptosis is induced as a result of disease or therapy, which is characterized in that the concentration of the apoptotic products in samples taken from patients is correlated with the effectiveness of the therapy and thus serves as a follow-up for the therapy. The serum samples are taken at various times and determined. The present invention in particular concerns a method in which the concentration of nucleosomes is determined in serum samples of tumour patients in order to assess the effectiveness of tumour therapy. Furthermore the present invention also concerns the use of a method according to the invention to determine the effectiveness of therapy in tumour patients who are subjected to a radiotherapy or chemotherapy treatment as well as in patients after an acute ischaemic event or after hypothermia treatment.