Abstract: The invention provides a method of isolating cells from a faecal stool, the method comprising the steps of a) cooling the stool to a temperature below its gel freezing point, and b) removing cells from the stool whilst maintaining the stool at a temperature below its gel freezing point such that the stool remains substantially intact. The invention further provides methods of purifying cells comprising use of immunomagnetic beads and/or boric acid. Cells isolated according to the invention may be used in diagnostic tests and assay procedures for monitoring a biological or biochemical property of tissue.