Abstract: Apparatus for collecting body liquids from a patient comprises a reservoir connectible to a patient to collect body liquids therefrom. A filter in the reservoir is interposed between an air vent and a liquid receiving zone in the reservoir. The filter faces generally upward within a chamber which is disposed near the top of the reservoir and is closed to the reservoir except for at least one restrictive orifice communicating between the reservoir and the top of the chamber. The restrictive orifice opens to the reservoir near the top of a boss upstanding from the top of the chamber and opens to the chamber at a location radially outboard of the filter. A barrier depends from the top of the chamber radially between the restrictive orifice and filter. A bowl supports the filter and has a bottom spaced above the bottom of the chamber to define a liquid receiving sump therebetween.