Data are presented about a 100 cases prospective study, designed to evaluate sensibility/specificity of intra-operative cytology on peritoneal washing in case of cancer of digestive tract. Data analysis showed a very low sensibility of the test (according with most of literature observations) that does not allow to consider it fully reliable. Authors, thus, suggest a critical use of the test and state doubts about his real value in the intra-operative correct managing of therapeutic options.