Emergencies in pituitary disease are not common. They can result from the failure of the pituitary gland to secrete one or more pituitary hormones, or from neuro-ophthalmological symptoms due to the mass effect of an expanding hypothalamic-pituitary tumour. Loss of hormone secretion, particularly ACTH and, to a lesser extent, TSH, can rapidly become life-threatening and requires urgent replacement therapy. Acute severe hypopituitarism should be vigorously treated as an emergency with a glucocorticoid preparation. Neuro-ophthalmological symptoms such as visual impairment, sudden onset of severe headache and alteration of the level of consciousness should prompt appropriate radiological investigations, since this may well call for emergency surgery. © 1992 Baillière Tindall.