D-cycloserine, known as anti-tuberculotic medicine, has been widely used in neuropsychiatric studies, since it acts as a partial NMDA-agonist at low doses, at the glycine-binding site of NR1 subunit.[sup][33] We recently observed clinical improvement in one refractory case with anti-NMDAR encephalitis after administration of D-cycloserine (125–250 mg/d).