The present invention provides a highly effective device and method for performing human colon irrigation. It comprises a bypass line having a non-return valve connected to a warm water supply line where in the non-return valve operates in proportion to back pressure as it develops in the colon thereby allowing gentler filling of colon and limiting pressure in the colon to a maximum safe level. Benefits include patient comfort and a safeguard against damaging the intestine. The present invention also provides a novel housing for a colon irrigation device which provides easy access to the internal part of the device without the need for disconnecting water or electrical supply lines.