Development of swallowable wireless sensing capsules dates back to 1964 with the advent of the Heidelberg pH capsule. Transmission of data from the inside of the body by radiofrequency is still the mainstay of action. However, multiple sensors have been developed in the meantime and broadened the range of application: this includes sensors for detection of blood, pH, pressure, temperature, and different gases. Prepless detection of colonic polyps by wireless transmission of luminal fluoroscopy has been tested, as well as wireless control of capsules for intestinal drug delivery.