In this study we present a new technology to detect stable oligomeric protein complexes in membranes. The technology is based on the ability of small membrane-active alcohols to dissociate the highly stable homotetrameric potassium channel KcsA. It is shown via a proteomics approach, using diagonal electrophoresis and nano-flow liquid chromatography coupled to tandem mass spectrometry, that a large number of both integral and peripheral Escherichia coli inner membrane proteins are part of stable oligomeric complexes that can be dissociated by small alcohols. This study gives insight into the composition and stability of these complexes.