We have measured X-ray absorption spectra for acetic acid molecules in an organic solvent in order to study the effect of hydrogen-bonding formation. The spectral shapes distorted by saturation effect were compensated by using a new correction procedure for X-ray absorption based on the changes in the concentration of the samples. A resonance peak shift was observed when the acetic acid molecules formed a cyclic dimer in hexane solution, which is similar to the behavior of cluster molecules in vacuum. This is the first report on the XAS spectral changes due to cyclic dimer formation in a solution. (C) 2011 Elsevier B. V. All rights reserved.