Stellate ganglion block is a selective sympathetic blockade affecting one side of the head and neck, and the upper extremity and upper part of the thorax on the same side. It is an important method of treating impaired vascular circulation, sympathetic reflex dystrophy, causalgia and herpes zoster in the area other indications, e.g. acute hearing loss and retinal arterial spasms, are still disputed. The anatomy of the cervical sympathetic chain, the technique used to achieve the block (paratracheal access) and tests of the effectiveness of stellate ganglion blockade are described. The side-effects and complications of the method and other means of sympathetic blockade are discussed. Patients need to be informed of the possible complications and the alternatives available before being asked to give informed consent.