Apparatus for measuring electrical characteristics of biological tissues includes an autonomous capsule with an external surface having openings, a plurality of electrodes located within the openings, and a processor in communication with the plurality of electrodes for generating electrical characteristics. A method for measuring electrical characteristics of biological tissues includes the steps of introducing into the digestive tract an autonomous electrode configuration, selecting sets of electrodes for measurement, introducing a current into the selected electrodes, collecting electrical data from the selected electrodes, and calculating electrical characteristics from the collected data.