In this study, to valorize the pomegranate peels, the phytochemical composition of the methanolic extract of Punica granatum L. peel (PPME) was characterized by high-resolution liquid chromatographymass spectrometry (LC/HRMS), while the mineral composition of the extract was determined by ICP AES. In the methanolic pomegranate peel extract, thirty-five different compounds were identified by LC/HRMS, and it was determined that these compounds were mainly terpenoids, lipids and flavonoids. Total polyphenol, flavonoid, and tannins contents of the PPME extract were determined as 211.43 mg GAE/g polyphenol, 20.7 mg QE/g flavonoids and 11.5 mg TEA/g tannins. In order to determine the antioxidant capacity of the extract, we studied its 1,1-diphenyl-2-picryl-hydrazyl radicals (DPPH.) and reducing power activity assays. These colorimetric assays showed that PPME has strong reducing power and anti-radical capacity against DPPH with the IC50 values 0.210±0.005 mg/mL and 0.3±0.0045 mg/mL, respectively. Our findings clearly show that the methanolic extract of PPME contains two potent compounds against gastric ulcers compared to the reference drug, esomeprazole.