Editor,—On the basis of a study reported recently by Neurath et al(Gut1999;44:625–628), commentaries inGut 1 and theLancet 2 suggested that mycophenolate mofetil (MMF) should be used in patients with Crohn's disease who have either not responded to or are intolerant of azathioprine or 6-mercaptopurine. This advice is premature: firstly, because the study was flawed and, secondly, because it examined only management of acute inflammation, not the place of MMF in maintaining remission and in steroid sparing (a fact acknowledged in both commentaries).

The study by Neurath et al compared the effect of MMF 15 mg/kg daily with azathioprine 2.5 mg/kg daily, both with high dose steroids, in the treatment of active chronic Crohn's …