For the study, the HemoPill acute capsule was swallowed by the patient and a special extracorporeal receiver was positioned next to the patient's body. The receiver recorded sensor signals from the ingested capsule for the next 4 hours. Patients who had swallowed a capsule underwent endoscopy within the next 12 hours. Later, both the endoscopic pictures and the endoscopy report were compared to the sensor capsule data recorded in the extracorporeal receiver. Furthermore, the excretion of each HemoPill acute capsule was monitored in accordance with the study protocol (regular check to see if sensor signal was still detectable from inside the patient's body) for a follow-up period of 10 days.