Aceclofenac belongs to a group of NSAIDs characterised by a strong anti-inflammatory effect. Although it was assumed that it is a prodrug of diclofenac, this is not a completely true statement. Recent pharmacokinetic studies have shown that aceclofenac is slightly metabolised to diclofenac in humans, reaching only a few per cent. The absence of a strong association between diclofenac and aceclofenac is also supported by the results of clinical trials that directly compare these two drugs. Aceclofenac is an effective drug with a good safety profile, especially for side effects from the gastrointestinal tract, compared to diclofenac and non-selective cyclooxygenase inhibitors. In addition, this drug has a protection effect for articular cartilage.