Antiseizure drugs used in the chronic treatment of epilepsy are administered orally; the objective is to prevent the occurrence of seizures. The choice of medication depends either on the type of seizures that the patient exhibits or on the patient’s syndromic classification. Appropriately chosen antiseizure drugs provide adequate seizure control in about two-thirds of patients. In designing a therapeutic strategy, the use of a single drug is preferred, especially in patients who are not severely affected; such patients can benefit from the advantage of fewer adverse effects using monotherapy. For patients with hard-to-control seizures, multiple drugs are usually used simultaneously. Patients who do not achieve seizure control following adequate trials with two or more appropriate drugs are considered “pharmacoresistant.” The basis for pharmacoresistance is not well understood. In children, some severe seizure syndromes (catastrophic childhood epilepsies) associated with progressive brain damage are very difficult to treat. Focal seizures may also be refractory to medications. In some cases, the epilepsy can be cured by surgical resection of the affected brain region. The most commonly performed epilepsy surgery is temporal lobe resection for mesial temporal lobe epilepsy; extratemporal cortical resection, when indicated, is less successful. When seizures arise from cortical injury, malformation, tumor, or a vascular lesion, lesionectomy may be curative. In addition to medications and surgery, several electrical stimulation devices are used in the treatment of epilepsy. The vagus nerve stimulator (VNS) is an implanted programmable pulse generator with a helical electrode that is wrapped around the left vagus nerve in the neck. The device, which continuously delivers open-loop stimulation according to a duty cycle, is approved for the treatment of drug-refractory focal seizures but may also be a good option for symptomatic (or cryptogenic) generalized epilepsies of the Lennox-Gastaut type, including those with intractable atonic seizures. Another device for the treatment of medically refractory focal epilepsy is the responsive neurostimulator (RNS). The RNS is a closed-loop system that detects a pattern of abnormal electrical activity in the seizure focus and then delivers electrical stimulation to prevent seizure occurrence. Other devices, using various paradigms of electrical stimulation, are in clinical development. One of these, a deep brain stimulation device, has been approved in Canada and Europe but not in the USA.