An organ transplant can replace an organ that is failing. Transplants can be done on livers, kidneys, hearts, lungs, and the small intestine. There are times when a double organ transplant will be required, such as heart/lung.
A liver transplant will be needed when the liver goes into failure. This can be caused by illness such as hepatitis. It can also be caused by cirrohsis of the liver. Certain medications can also cause liver failure.
A kidney transplant will be needed when the kidneys are affected by diseases such as diabetes, polycystic kidney disease, or lupus. If one kidney is transplanted, it can be done by what is called live organ donation. In this case, a living person gives one kidney to another person with bad ones. We can live with one kidney so this will work. A living donor may include a family member, friend or coworker or anyone willing to give a kidney. A kidney from someone who has died can also be used. In either case, the kidney will have to be the perfect match to work. This is why family members are usually the best candidates as donors in live donations.