We are mainly interested in the permeability of cell membranes for CO2 and O2 and the underlying molecular mechanisms. As main factors determining these permeabilities we have so far identified gas channels such as aquaporin and Rhesus-associated glycoprotein as well as membrane lipid composition. Major techniques are gas mass spectrometry and stopped flow spectroscopy for determination of membrane gas permeabilities, and preparation of liposomes with or without reconstitution of gas channel proteins, cell culture and isolation of primary cells from tissues. These techniques are complemented by the investigation of red cells from patients deficient in one of the gas channels, together with in vivo and in vitro studies of gas channel-knockout mice or their tissues.