Four members of the NICE guideline development committee for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) left the group just weeks before the final guideline was due to be published, The BMJ has learnt. The departures suggest divisions within the committee over the guideline’s final content, which is an update on 2007 guidance on diagnosing and managing ME/CFS. Three have resigned, and one has been removed by NICE. The draft guidance, published in November 2020,1 included significant changes to the 2007 recommendations2 and raised questions about how the evidence could have shifted so substantially. In 2007 NICE recommended interventions such as cognitive behavioural therapy and graded exercise therapy for people with mild or moderate ME/CFS, whereas the draft update cites a “lack of evidence for the effectiveness of these interventions.” …