A human organ transplant is a medical procedure where a failing or damaged organ in a patient is replaced with a healthy organ from a donor. This can involve organs such as the heart, kidneys, liver, or lungs. Transplants are often necessary for patients with severe organ failure due to conditions like heart disease, kidney disease, or liver cirrhosis. Donors can be living or deceased, and the matching process is crucial to ensure compatibility between the donor and recipient. After a successful transplant, patients typically require lifelong medication to prevent their bodies from rejecting the new organ.