Enterocytes are constantly shedded from the top of the intestinal villi into the lumen at a rate of 20·106/min. If these enterocytes are still viable they could be used to study the expression and function of drug metabolizing enzymes and transporters in the gut wall. Methods: To collect the shedded enterocytes, we developed and used an intestinal perfusion silicone rubber twelflumen catheter (04,2mm) with four balloons in six healthy male subjects. The two isolated small intestinal segments were perfused (2ml/min) with a buffer and the perfusate was collected continuously. Results: 1. The P450 content was 185 pmol/mg microsomal protein. 2. 80% of the cells were in G1-phase and only 20% positive for apoptosis. 3. The viability of the cells was shown by trypane-blue. 4. Western-blot and RT-PCR of P-gp, CYP2D6, CYP3A and CYP2C exhibited amounts of protein and RNA comparable to hepatocytes. 5. Assays for drug metabolism (CYP2D6, CYP2C, CYP3A) yielded activities of same order of magnitude as in liver. Conclusion: This catheter is an efficient method to collect shedded enterocytes for the study of gut wall metabolism.