Abstract A capillary zone electrophoretic method was used to obtain profiles of solubilized rat hair keratin proteins. The same methodology was used to reveal the presence of additional protein peaks in alcohol-consuming rats. Two types of separation were investigated. Alkali-solubilized keratins from hair of rats treated for 5 weeks with 5% ethanol and 2 weeks with 10% ethanol (instead of drinking water) and from controls were analysed. Whereas under alkaline conditions (pH 9.2, 50 mM borate) an additional fraction of "low-sulphur" keratins with the highest anodic mobility of this keratin category was shown in alcohol-treated animals, acid electrophoresis carried out at pH 3.5 in phosphate buffer (50 mM) revealed the presence of two sharp peaks absent in the controls. These findings were confirmed by two-dimensional separations of carboxymethylated keratin samples. An attempt was made to identify further one of the newly occurring fractions in alcohol-consuming animals. It was revealed that the tryptic hydrolysate of "low-sulphur" proteins obtained from alcohol-consuming animals contained a peptide not found in controls