NSAID means Non-Steroidal Anti-Inflammatory Drugs. Common NSAID drugs include aspirin, ibuprofen, diclofenac, etc. Most of us are aware of aspirin, which is actually a blood thinner used as medication for heart diseases. We are also aware of ibuprofen which is a known pain killer. It may sound surprising that prolonged use of NSAID drugs can cause peptic ulcer. What mechanism makes them cause peptic ulcer?