Phlebitis is inflammation of the veins, usually causing thrombosis (thrombophlebitis) and obstruction to blood flow. It is common in the superficial veins of the legs, especially in varicose veins, and visceral veins close to inflamed organs or abscesses. Phlebitis may complicate intravenous injections of drugs or indwelling cannulae for intravenous fluids. Pain, swelling, and erythema over the vein are typical with it becoming a thick tender cord. Occasionally phlebitis indicates systemic disease, such as cancer.