Ulcers that develop due to alcohol consumption are frequently confronted. The aim of this study was to investigate the protective effects of silk fibroin on the pro-apoptotic and anti-apoptotic protein expression levels on ethanol induced-ulcer models in rats. For three consecutive days, orogastrically either silk fibroin or saline were given to rats. On the 4th day, animals were deprived of food but allowed free access to water for 24 h before the experiment. While control groups were treated with only physiological saline, the ulcer groups were treated orally either with saline or silk fibroin groups. For ulcer induction, 1 ml of absolute ethanol by gavage were given to both group. Firstly, intracardiac blood was taken at 60 min of EtOH or saline administration and immediately animals were decapitated. In blood samples, the amount of TNF-, IL-1ß were analysed whereas in stomach tissues, the levels of MDA, GSH, and MPO activity and the expression levels of bcl-2, Bax, caspase-3 and -9 were determined. In ulcer groups, the amount of TNF-, IL-1ß, MDA, MPO, caspase-3 and caspase-9 were found to be significantly higher compared to control groups whereas in GSH, Bcl-2/Bax were found to be lower (p < 0.005). In treatment groups it is observed that silk fibroin recovers the amount of TNF-, IL 1-ß, MDA, MPO, GSH, caspase-3, caspase-9, and Bcl- 2/Bax. In conclusion, for the treatment of the gastric ulcer SF thought to be very efficient therapeutic agent. [ABSTRACT FROM AUTHOR]