Poly (ADP-ribose) polymerase (PARP) inhibitors are a type of targeted therapy that blocks the activity of the PARP enzyme, which is involved in repairing damaged DNA in cells. By inhibiting PARP, these drugs prevent cancer cells from repairing DNA damage, leading to their death. PARP inhibitors have shown promise in the treatment of various types of cancer, particularly in patients with mutations in genes involved in DNA repair, such as BRCA1 and BRCA2. These inhibitors are being actively studied in clinical trials for their potential to improve outcomes for patients with breast, ovarian, prostate, and other types of cancer. Overall, PARP inhibitors represent a promising new approach to cancer therapy that exploits the vulnerabilities of cancer cells with DNA repair defects, and they have the potential to revolutionize treatment for a wide range of cancer types.