The term applied to a piece of tissue removed from one person or animal and implanted in another, or the same, individual in order to remedy some defect. Skin grafts are commonly used, and artificial skin for grafting is also available. Bone grafts are used to replace bone which has been lost by disease: for example, a portion of rib is sometimes removed in order to furnish support for a spine weakened by disease, after removal of the damaged bone. The bone of young animals is used to afford additional growth and strength to a limb-bone which it has been necessary to remove in part on account of disease or injury. Vein grafts are used to replace stretches of arteries which have become blocked, particularly in the heart and lower limbs. The veins most commonly used for this purpose are the saphenous veins (from the legs) of the individual in question, provided they are healthy. An alternative is specially treated umbilical vein. (See SKIN-GRAFTING.)

When a replacement organ, such as kidney, heart or liver, is ‘grafted’ into someone's body, it called a ‘transplant’ (see TRANSPLANTATION).