INTRODUCTION: Postoperative monitoring of free flaps with microdialysis allows early diagnosis of anastomotic complications. Feasibi-lity studies are required to examine flap accessibility for oral cavity reconstruction. CASES: We present our preliminary findings in two patients who underwent radial free flap reconstruction of the floor of the mouth. For the first patient, a microprobe was used to monitor the flap for 45 hours. In the second case, an abdominal microprobe served as a control in healthy skin with another probe located in the cutaneous flap for 4 days. Flap monitoring, starting from the recovery room, was successful with easy manipulations for the nurse. Correlation between the monitoring curves and the clinical aspect of the flap was excellent. DISCUSSION: The microprobe should be short (1 cm), and carefully anchored. Naso-gastric feeding is required during monitoring. A close correlation has been found between glucose level and systolic pressure. The use of a comparative microprobe in healthy abdominal skin is helpful in learning to use the dialysis curves.