Tissue damage due to extravasation does not occur frequently, but the consequences can be severe. Certain factors are important in determining the likelihood of extravasation injury. These include the age, state of consciousness, and venous circulation of the patient and the type, location, and placement of the intravenous cannula. Extravasation injury is induced most frequently by drugs that have high osmolalities, vesicant properties, or the ability to induce ischemia. Treatment includes elevation of the extremity, application of heat or cold, and the administration of an appropriate antidote. Prevention of extravasation injury requires recognition of potentially hazardous drugs and good technique in administering drugs intravenously.