Table 2

Colonic peri-mucosal pH in healthy volunteers and patients with ulcerative proctitis and neoplasia

Study	Method	Patients	Caecum/right colon pH	Left colon/ rectal pH
McDougall, 199314		Colonoscopy probe		21 normals	7.1	7.2–7.5
McDougall, 199314		Colonoscopy probe		37 neoplasia	7.2	7.2–7.4
McNeil, 198715		Microelectrodes, human rectal biopsies		6 normals	N/A	6.3–6.8
McNeil, 198715		Microelectrodes, human rectal biopsies		5 ulcerative proctitis	N/A	6.3–6.8