The fluorescence intensity of Rhodamine 6G (R6G) introduced on hydrotalcite by the rehydration method was determined to depend strongly on the alcohol vapor pressure, whereas that of R6G simply adsorbed on hydrotalcite had low dependence on the vapor pressure. The intensity decreased with an increase in pressure, and the change in intensity was reversible. The degree of change differed according, to the alcohol used and seemed to be related to the saturated vapor pressure of the alcohols.