The MARSIPAN (MAnagement of Really SIck Patients with Anorexia Nervosa) project was established in response to reports of patients admitted to medical wards and proving refractory to treatment, sometimes dying on the ward. Psychiatrists, physicians and other clinicians in nutrition and eating disorders were brought together to discuss key issues in the assessment and management of such patients. The resulting guidance report, which applies to adult patients over 18, addresses: assessment of risk, where to treat the patient, specialist support for medical teams, key elements of treatment, namely (a) safe refeeding to avoid refeeding syndrome and underfeeding syndrome, (b) management of problematic behaviours, (c) support for the family, and (d) transfer to a specialist eating disorder unit when appropriate and possible.