 As of 2015 the UK National Health Service had concluded that it could not be recommended for treating the symptoms of multiple sclerosis due a lack of evidence.Prescription and medical formulation of low-dose naltrexone in the UK are unlicensed in the treatment of multiple sclerosis.Although preliminary studies have been published on Crohn's disease, the small size and preliminary nature of the studies prevent drawing "any firm conclusions regarding the efficacy and safety of LDN used to treat patients with active Crohn's disease."