Multiple sclerosis (MS) is a disorder of the central nervous system with an inflammatory and a neurodegenerative component. We do not yet have a definitive therapy for MS. Attempts to develop new treatments are long and costly and should be paralleled by studies aimed at increasing the therapeutic index of the existing treatments, interferon beta and glatiramer acetate. Pharmacogenetics and pharmacogenomics may be of use in this respect though their application may not be straightforward, particularly in MS.