Systems, kits and methods are provided, which analyze the large intestine content and utilize acoustic signals detected during delivery of water into the large intestine and drained large intestine contents to derive large intestine characteristics such as microbiotal analysis. Systems may include a water delivery unit including a water supply and a nozzle connected thereto, configured to introduce water controllably into a patient's large intestine, and an analysis unit that provides information about the drained contents using optical examination or biological assays. The information may be related to acoustic analysis of signals from acoustic sensors that are attachable to a patient's abdomen. A variety of sensor configurations, positioning options, analysis strategies and large intestine characteristics are presented.