Starting from the effects of volatile anaesthetics on the structure of bacteriorhodopsin (bR) in the purple membrane in solution this work tries to investigate the interaction of ether and hydrocarbon type anesthetics vapors with self-assembled bR thin films, a dedicated constant flux chamber has been built to maintain the sample in a rather constant atmosphere of anesthetics, during the absorption measurements. The kinetics of absorption and desorption have been determined. The results obtained have been compared with those of bR in solution.