A predominantly adrenaline-secreting phaeochromocytoma. A 61-year-old woman who presented with diabetes, nausea, weight loss and sweating was found to have a phaeochromocytoma secreting adrenaline, with a small amount of N-methyladrenaline. There was no significant increase in noradrenaline secretion. She was normotensive, and developed profound hypotension in response to the alpha-adrenergic antagonist phenoxybenzamine. These features are unusual in phaeochromocytoma, but similar features occurred in the very few previous reported cases of pure adrenaline-secreting phaeochromocytoma. We conclude that it is important to identify such patients, so that they should not be given alpha-adrenergic antagonist drugs. 