Cimzia is a prescription medication used to treat various autoimmune conditions, including rheumatoid arthritis, Crohn's disease, and psoriatic arthritis. It contains the active ingredient certolizumab pegol, which works by inhibiting a protein called tumor necrosis factor-alpha (TNF-alpha) that contributes to inflammation in the body. Cimzia is administered through subcutaneous injections, typically every two to four weeks, depending on the condition being treated. Patients should discuss potential side effects and any necessary precautions with their healthcare provider before starting treatment.