Yes, Celebrex (celecoxib) 200mg can cause side effects, though not everyone experiences them. Common side effects include stomach pain, indigestion, diarrhea, and mild dizziness. Some users may also experience headaches or mild swelling. While rare, serious side effects like heart problems, high blood pressure, stomach bleeding, or kidney issues can occur, especially with long-term use. Allergic reactions (rash, difficulty breathing) are also possible. Always take Celebrex as prescribed and consult your doctor if side effects worsen.