Undifferentiated neurological presentations are not uncommon to the ED. Vitamin B (12) deficiency can lead to progressive demyelination and axonal lesions on the peripheral nerves and cervicothoracic spinal cord causing a peripheral neuropathy. Nitrous oxide is a common adjuvant to anaesthesia in the ED but it not often thought of as a drug of abuse. A case is reported of prolonged and intensive nitrous oxide abuse that resulted in the development of a peripheral neuropathy.