ABSTRACTObjective. To evaluate the pharmacological, clinical and toxicological effects of celecoxib and meloxicam for analgesia for 30 days in dogs with hip osteoarthritis. Materials and methods. Twenty-four patients were evaluated, 75% were females with an average age of 7.16 ± 2.06 years and twenty five percent were males with an average age of 7.83 ± 2.22 years. All patients had hip osteoarthritis and they were randomized into two groups; one group received oral celecoxib 5 mg/kg every 12 hours during one month and the second group received oral meloxicam 0.2 mg/kg every 24 hours during 1 month. The patients were evaluated for analgesia, and hematological, renal, liver, and coagulation tests on days 0, 10th and 30th after treatment initiation, and a gastric endoscopy on day 30. Statistical analysis was performed using a HSD Tukey test and c2 with a 5% level of statistical significance. Results. Both drugs reduced articular pain according to the Melbourne scale during the 30 days of treatment (p≤0.05). Hematological, renal, hepatic and coagulation tests were normal in both treatment groups. All patients presented chronic gastritis on endoscopy on day 30th. Conclusions. Both drugs decreased pain at day 30th without causing alterations in hematological, renal, hepatic or coagulation tests after 30 days of treatment. However, both drugs induced chronic gastritis.