Acemetacin is a non-steroidal anti-inflammatory drug, used for the treatment of osteoarthritis, rheumatoid arthritis, lower back pain, and relieving post-operative pain. It is manufactured by Merck KGaA under the tradename Emflex, and is available in the UK as a prescription-only drug. Other brand names for acemetacin include Rheutrop (Austria), Acemetadoc, Acephlogont, Azeat, Rantudil (Germany, Mexico, Portugal), Gamespir (Greece), Oldan, Reudol (Spain), Tilur (Switzerland), Ost-map (Egypt).

Acemetacin, a glycolic acid ester of indometacin, acts as a prodrug; in the body, it is metabolized to indometacin, which then acts as an inhibitor of cyclooxygenase, producing the anti-inflammatory effects. An advantage of acemetacin is that it reduces gastric damage when compared to indometacin.