The present invention relates to the use of aminoguanidine compounds for treating diseases of the nervous system. Aminoguanidine compounds can be used as therapeutically effective agents against a variety of diseases of the nervous system such as diabetic and toxic neuropathies, peripheral nervous system diseases, Alzheimer's disease, Parkinson's disease, stroke, Huntington's disease, amyotropic lateral sclerosis, motor neuron disease, traumatic nerve injury, multiple sclerosis, dysmyelination and demyelination disorders, and mitochondrial diseases. The aminoguanidine compounds which can be used in the present method include (1) aminoguanidine and diaminoguanidine analogs which can act as substrates or substrate analogs for creatine kinase; (2) bisubstrate inhibitors of creatine kinase comprising covalently linked structural analogs of adenosine triphosphate (ATP) and aminoguanidine; (3) aminoguanidine analogs which can act as reversible or irreversible inhibitors of creatine kinase; and (4) N-phosphoroaminoguanidine analogs bearing nontransferable moieties which mimic the N-phosphoryl group.