The purpose of gene therapy in medicine is to treat or prevent disease by modifying or replacing genes within an individual's cells. This innovative approach can target genetic disorders caused by mutations in specific genes, allowing for correction of faulty genes or introduction of new genes to enhance healing or disease resistance. Gene therapy can employ various methods, including the use of viral vectors to deliver therapeutic genes. Its applications range from treating genetic diseases to combating cancers and certain viral infections, representing a promising frontier in precision medicine.