Amiodarone-induced thyrotoxicosis (AIT) presents a therapeutic challenge because of its resistance to standard antithyroid therapy. In iodine-deplete environments, colour-flow Doppler sonography (CFDS) has allowed distinction between two types of AIT: (i) Type I AIT, associated with increased vascularity (CFDS I-III) and response to thionamide antithyroid drug and (ii) type II AIT, with no/little thyroid vascularity (CFDS 0) and prednisolone responsiveness.