Anastomotic leakage after esophagectomy and esophagogastrostomy depends on the vascularization of the gastric conduit. So far, no adequate methods are available to monitor postoperatively mucosal microcirculation of the gastric conduit. The aim of this experimental study was to assess a recently developed microprobe with a microlight-guide spectrophotometer (O2C, Fa. LEA Medizintechnik, Giessen, Germany) to quantitatively measure gastric mucosal blood flow (MBF) and mucosal oxygen saturation (MOS) of different gastric areas. Eighteen patients without gastric pathology were included in this study. During conventional gastroscopy the microprobe was introduced via the working channel of a standard endoscope and positioned in well-defined areas of the antrum and fundus. The tip of the microprobe consisted of a combined laser Doppler and tissue spectrometer measuring continuously the MBF (perfusion units, PU) and MOS (SO(2), in %). The mean MOS of the antrum was significantly higher compared with the fundus (antrum: 82% +/- 7.9 standard deviation [SD], fundus: 72% +/- 10.4; P = 0.0002). The mean MBF was not significantly different between antrum and fundus (antrum: 201 PU +/- 40 SD, fundus: 223 PU +/- 29 SD). This study demonstrates the feasibility of the gastric O2C microprobe to measure parameters of gastric microcirculation from the endoluminal side.