A rectal appliance with a tubular member defining a communication passage for body waste, and first and second inflatable chamber portions carried on the tubular member for forming internal and external seals with respect to the anus. One or both of the inflatable chamber portions have a partly flared shape. The second inflatable chamber portion has a low external profile, and a concave sealing surface. The inflatable chamber portions are defined at least partly by a common flexible membrane that is constrained near a middle region to define a narrow waist between the two inflatable chamber portions.