Infantile spasms are the main feature in West syndrome, an age-related epilepsy syndrome that affects 1 in every 2,000–4,000 infants. The authors provide a comprehensive review of the literature about infantile spasms and their therapy. In the United States, the drug of choice for infantile spasms, at least the cryptogenic cases, has been adrenocorticotropic hormone (ACTH). It is generally considered to be more effective than corticosteroids. Adrenocorticotropic hormone appears to alter long-term prognosis of cryptogenic infantile spasms, and helps in some cases of symptomatic infantile spasm. Vigabatrin has been considered the drug of choice for infantile spasms secondary to tuberous sclerosis, and possibly, according to many neurologists, for all cases of infantile spasm. Recent concerns regarding retinopathy associated with vigabatrin therapy are, however, limiting the use of this drug. Valproic acid benefits 40%–70% of patients who failed a trial of ACTH. Nitrazepam is as effective as ACTH in acutely controlling infantile spasms; however, its long-term effects on prognosis have not been studied. Pyridoxine, lamotrigine, topiramate, zonisamide, ketogenic diet, immunoglobulin therapy, felbamate, and thyrotropin-releasing hormone have all been used for the treatment of infantile spasms, but are usually reserved for cases refractory to vigabatrin and/or ACTH.