A new method to test the sensitivity of human tumor cells has been developed. A suspension of mechanically dissociated tumor cells is kept in continuous incubation for 24h, in cultures with antineoplastic agents. Drug induced cell cycle perturbations are monitored by flow cytometric computer analysis and DNA distributions of the cells stained with propidium iodide are expressed in percentage. The test is used in 15 head and neck human solid tumors. The drugs tested were: VCR, EpiDx, CDDP, MTX, 5-FU, CPM, BLM. The results obtained reveal that tumor sensitivity varies independently from the stage and malignity grading. Therapeutic combinations are assigned by selecting the drugs on the basis of the individual in vitro response.