PhotoBarr must not be used in patients with porphyria (an inability to break down porphyrins), severe problems with the liver or kidneys, varices (swollen veins) in the oesophagus or stomach, large ulcers in the oesophagus, fistulae (abnormal passageways) between the oesophagus and either the trachea (windpipe) or the bronchi (airways in the lungs), or suspected damage to major blood vessels.