Nevertheless, several contraindications or possible reasons of concern should be considered prior to prescription, such as use in children—except of severe or otherwise intractable cases, during pregnancy, in patients with autoimmune diseases, liver dysfunctions, medication with CYP1A2 inhibitors [35], and, unless the issue is definitely settled, Parkinson's disease and irritable bowel syndrome type II, which have both been interpreted as diseases of melatonin overproduction (“melatonin hyperplasia”) [235]. The gene discussed is CYP1A2; the disease is autoimmune disease.