This study is an effort to follow diabetic patients who have peripheral neuropathy, and prefer to buy the drug Tolrestat, in Mexico rather than participate in the Double-Blind drug trial of this study. They do not want to be on placebo. We will monitor their sural nerve MRI water content, but more importantly, for their safety, to recommend periodic assessment of their liver function, CBC, and a physical exam. It is hoped to gain useful information about the MRI sural nerve water.