We present an unusual cause for syncope that was initially thought to be due to drug therapy. Further investigations revealed the cause to be secondary to hypoadrenalism from a primary breast tumour. This case highlights the importance of arriving at the right diagnosis as signs and symptoms of adrenal insufficiency can mimic other conditions. Appropriate treatment also improves quality of life. (C) 2006 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.