The present invention relates to a capsule device for in vivo imaging and pH measuring of the esophagus, said capsule device having an optical window (1) and comprising at least one illumination source (2) for illuminating an esophagus site at least one imaging camera (3) an optical system (4) for imaging the esophagus site onto the imaging camera (3) a transmitter (5) for transmitting pH measurement and video output of the imaging camera (3) a pH electrode (8) and a reference electrode (9) means for transmitting pH measuring data to a recording and/or analyzing unit and at least one fixing means (10) for fixing the capsule device preferably at the mucosa of the esophagus. Optionally, the capsule device can comprise or can be connected to a pressure transducer catheter.
