Background: Chronic pain is the major complaint in subjects with osteoarthritis (OA). Non- steroid anti-inflammatory drug (NSAID) is still the drug of choice in Indonesia to treat OA patients. The prolonged consumption of NSAID may lead to many adverse events (AE). Some previous studies showed the extract of Curcuma longa and Boswellia serrata is a promising potential as therapeutic interventions against OA. Objective: This study aimed to evaluate the effectiveness and safety of CB extract to relieve symptoms in patients with OA Study Design: This was a randomized controlled trial (RCT) in OA patients. The treatment used in this trial were CB extract (350 mg of Curcuma longa and 150 mg Boswellia serrata) and NSAID (400 mg ibuprofen or 50 mg diclofenac sodium). Subjects were randomized to 3 different groups (Group 1: CB extract and NSAID; group 2: CB extract; group 3: NSAID). Each medication was taken two times per day for four weeks. Paracetamol tablet 500 mg gave to each subject as a rescue medication. Each subject would be followed up three times: baseline (visit I), two weeks after baseline (visit II), and four weeks after baseline (visit III). The measurement was using WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index).