Thirty-seven years' experience in diagnosing and treating thousands of patients who have hypothyroidism has illustrated to the author that this chronic affliction not only occurs frequently in the Middle West but, more unfortunately, often goes unrecognized. The primary reason for overlooking hypothyroidism is the placing of too much reliance on a single metabolic test. Such a test rarely registers lower than it should, in contrast to frequent false-high readings. Equally important as the metabolic test is symptomatology; one of the most frequent complaints, seldom mentioned in the literature, is that of headache. In treating hypothyroidism the potency of various thyroid preparations must be given as much consideration as the dosage, for the successful results can depend as much on the use of strictly fresh tablets as on the administration of them.