Thyrotoxicosis is a generally common endocrine condition. Widespread radiologic studies and interventional treatments can increase the prevalence of contrast-induced thyrotoxicosis. A younger Thai female was diagnosed acute appendicitis that underwent computed tomography of abdomen with contrast injection. After the operation, she had fever and tachycardia without source of infection, but her thyroid function test showed hyperthyroidism, so she was diagnosed graves' disease and received the treatment without thyroid storm. Graves' disease is the most prevalent cause of hyperthyroidism in women but there are many causes of hyperthyroidism especially contrast-induced hyperthyroidism in this care, so the necessary of diagnostic tools especially contrast computed tomography should be carefully used in some patients. Critical radiologic studies and interventional procedures can increase the prevalence of contrast-induced thyrotoxicosis, particularly in high-risk patients. Utilizing a multidisciplinary team, clinicians must promptly address thyrotoxicosis and avert the thyroid storm.