Patients with multiple sclerosis were found to have increased cerebrospinal fluid, noradrenaline, and excitatory amino acid (glutamate and aspartate) levels, with increased blood glutamine, asparagine, and glycine levels. An association was found between these biochemical parameters and the nature and severity of neurological symptoms, as well as with the course of the disease. Neurotransmitters are proposed to have a role in the pathogenesis of multiple sclerosis, particularly in the biochemical mechanisms of the relationship between the nervous and immune systems, as well as in the neurochemical mechanisms underlying the development of neurological deficit.