In this study, it was aimed to investigate the gastroprotective and anti-inflammatory effects of the extract (TO) obtain from the leaves of Taraxacum officinale, which is used in the treatment of many diseases including gastric ulcers in traditional medicine, in an indomethacin-induced gastric ulcer model. Forty rats, which 10 animals in each group, were divided into four groups (Control (C), TO + Indomethacin (TO+IND), Indomethacin (IND) and Omeprazole + Indomethacin (O+IND) groups). Respectively the group C was given isotonic saline, the group TO+IND was given 100 mg/kg TO extract, group IND was given isotonic saline and the group O+IND was given 5 mg/kg omeprazole orally. On the 11th day of the study, a single dose of 100 mg/kg indomethacin was administered orally to the TO+IND, IND and O+IND groups. It was determined that cyclooxygenase-2 (COX-2), C-reactive protein (CRP) and Interleukin-6 (IL-6) levels were significantly increased in the IND group compared to the K group (p<0.001). However, these markers were significantly decreased in both the TO+IND (respectively p<0.05, p<0.001, p<0.05) and O+IND (p<0.05, p<0.001, p<0.001, respectively) groups when compared with the IND group. No significant changes were observed in tumor necrosis factor-alpha (TNF-α) levels. Depending on the administration of indomethacin, it was found that the ulcer index of gastric tissue increased significantly compared to the C group but it decreased significantly as a result of TO and Omeprazole administrations (p<0.001). As a result, it was determined that Taraxacum officinale leaf extract showed significant gastroprotective effects by reducing COX-2, CRP and IL-6 levels and ulcerative area formation in gastric tissue.