"Spironolactone bodies," or intracytoplasmic acidophilic inclusions, are reported to occur in the zona glomerulosa of adrenal cortices of patients treated with spironolactone, an inhibitor of aldosterone. These phospholipid-containing bodies, as disclosed by electron microscopy, are concentric whorls of smooth membranes arranged in a pattern similar to that in many organs under experimental conditions. A discussion of their significance falls into one of four broad areas, namely: artefactual, degenerative, regenerative, and functional. Although the spironolactone body's relationship to the drug spironolactone is unclear, the authors believe that these structures represent a compensatory attempt on the part of the cell to produce increased mineralocorticoid.