Abstract This cohort study aims to assess the outcomes of fibromyalgia patients enrolled in the UK Medical Cannabis Registry prescribed a homogenous selection of cannabis-based medicinal products (CBMPs). A cohort study of fibromyalgia patients treated with oils (Adven®, Curaleaf International, UK), dried flower (Adven®, Curaleaf International, UK) or both CBMPs was performed. Primary outcomes were changes from baseline at 1, 3, 6 and 12 months in validated patient-reported outcome measures. Secondary outcomes included descriptive analysis of adverse events. One hundred and forty-eight participants were treated with oils (n = 77; 52.03%), dried flower (n = 14; 9.46%) or both (n = 57; 38.51%). Improvements in the generalized anxiety disorder-7 questionnaire, single-item...