A post menopausal female with severe vomiting and weight loss in association with elevated thyroid hormone levels is presented. Signs and symptoms of thyrotoxicosis were not evident at presentation. Possible pathophysiological mechanisms and treatment are discussed. Antithyroid therapy with carbimazole and propranolol induced rapid resolution of her symptoms and marked improvement in well-being. Radioactive iodine ablation of her thyroid gland was performed later and she has remained asymptomatic.