An autonomic disorder of the circulatory system becomes manifest as aberrant heart rate variability and baroreflex sensitivity already years before progressing into symptomatic disease, in which case the condition is no longer curable. Diagnosis is based on tests of autonomic nervous system function. The main thing in the treatment is management of risk factors of cardiovascular diseases in addition to enhanced glucose homeostasis. Autonomic neuropathy may also affect the digestive tract and be accompanied by esophageal motility disorder, gastroparesis, diarrhea, constipation or fecal incontinence. It is essential in the diagnosis to exclude other diseases of the digestive tract.