Treatment of the physical complications of anorexia nervosa patients is an imperative and often requires specialist intervention in addition to psychotherapy. Through the Chiba Prefectural Eating Disorder Support Center Hospital and the National Eating Disorder Support Center Consultation Hotline, we have provided telephone and e-mail consultation since 2017. Consultation includes where to seek medical care and how to deal with patients with eating disorders, matters concerning families, and information about medical facilities. At the starting of the support center activities, to improve medical cooperation we conducted a survey of 3,137 medical facilities in Chiba Prefecture that have internal medicine, psychosomatic medicine, psychiatry, obstetrics, gynecology, and pediatrics departments that treat eating disorder patients. The results of this survey indicate that: 1) Patients with a BMI of less than 15 kg/m² would be most effectively treated by departments of psychosomatic medicine or psychiatry in general hospitals, 2) The types of assistance that the psychiatry departments expect from the internal medicine departments are blood sampling, nutritional therapy such as infusions, electrocardiography, and x-ray examinations, 3) Internal medicine departments expect assistance with specialized psychotherapy by the psychiatry and psychosomatic medicine departments.
 We have developed manuals that address these items and have distributed them free of charge on the Web. Furthermore, we set up the "Chiba Prefecture Eating Disorder Study Group" to promote medical collaboration through the discussion of case studies. The average number of consultations in Chiba Prefecture was 65.0 per month. The most common types of consultation were on where to see a doctor (36%) and questions about the disease (27%). 44% of consultations were from mothers and 30% from the patients themselves. As a result of these medical cooperation activities, the proportion of referrals to the core hospital (Kohonodai Hospital) decreased from 94% in 2017 to 19% in 2021. The number of referring hospitals also increased. For the 'Consultation Hotline' activities, the content and consultants were similar to those of the support center activities. Many of the consultations were from residents of prefectures with large populations where there was no support center.
 Authors' abstract