Aim of the present work was the development of a mechanic cell separation protocol for gastrointestinal biopsy analysis. Evaluation of the technique was performed on selected group of patients who underwent routine endoscopy. Routine gastrointestinal biopsies were obtained after informed consent. 23 gastric (6 healthy, 14 gastritis, 3 adenocarcinoma) and 15 colon samples (5 healthy, 7 colitis ulcerosa, 3 adenocarcinoma) were evaluated. The mechanic disruption of the biopsies was performed by Medimachine (DAKO, Denmark), a commercially available system using a 30 microns miner and a 30 microns mesh. The cell solution was centrifuged for 5 minutes by 250 g. The cells were fixed in paraformaldehide and stained by propidium iodide. The flow cytometry analysis was performed on a BD FacStar Plus flow cytometer. The DNA data were evaluated using the Winlist software. All of the preparations were appropriate for flow cytometric analysis. The coefficient of variation of the DNA histograms (n = 7) (CV mean +/- SD. 6.45% +/- 1.21) were acceptable for analysis. In the gastric biopsy samples aneuploidy was determined only in malignant cases. In four of the seven colitis ulcerosa samples and in one of the three adenocarcinoma aneploidy was found. The histologically healthy specimen were all diploid. Mechanic cell separation and disaggregation is a useful method for preparing fresh biopsy specimen for flow cytometry.