We treated a girl with Zellweger syndrome using a special infant formula supplemented with middle chain triglyceride (MCT) milk, docosahexaenoic acid (DHA), Lorenzo's oil, and Lunaria oil, which is rich in nervonic acid (C24: 1). We examined the fatty acid contents of the plasma and red blood cell (RBC) membrane. Neurological development was evaluated using Denver developmental screening test and auditory brainstem response (ABR). Her delayed neurological development, liver dysfunction, and cholestasis were all improved 2 weeks after starting the dietary treatment. DHA level in RBC membranes was increased and very long chain fatty acid (VLCFA,C26:0) levels were decreased. Our findings suggest that the dietary treatment with combination of MCT milk, DHA, Lorenzo's oil, and Lunaria oil in the patients with Zellweger syndrome bring some benefits for neurological development. (c) 2007 Elsevier B.V. All rights reserved.