OBJECTIVE: Gastrointestinal discomfort is one of the main adverse events in patients treated with mycophenolic acid (MPA). The aim of this prospective study was to evaluate the effect of conversion from mycophenolate mofetil (MMF) to enteric-coated mycophenolate sodium (EC-MPS) in liver transplant patients with gastrointestinal side effects. MATERIALS AND METHODS: A single center, open-label, single arm, prospective study was undertaken in previous MMF-treated liver transplant patients who stopped MMF due to gastrointestinal side effects. Patients were rechallenged with the same dose of MMF which previously provoked the discomfort. Subsequently, patients with gastrointestinal complaints were switched from MMF (mean dose, 1325 mg [interquartile range (IQR), 750-2000 mg]) to equimolar doses of EC-MPS (mean dose, 858 mg [IQR, 525-1170 mg]). RESULTS: Twelve patients received a rechallenge and 10 patients experienced complaints again. These patients (4 males, all Caucasian) of ages 14 to 68 years (mean, 54.5 years) were included in the study. There was a decrease in Visual Analogue Scale (VAS) of upper and lower gastrointestinal discomfort/pain between baseline to month 3 from mean 3.9 to 1.75 and from mean 7.6 to 0.2. The number of stools decreased from a mean of 2.25 (IQR, 1.4-2.9) to 0.5 (IQR, 0.3-0.625)/d and mean maximal stool frequency from 3 (IQR, 2-3.5) to 0.9 (IQR, 0.5-1.25)/d. No patients developed rejection. There was no graft loss. No significant changes occurred in hematological or biochemical parameters. CONCLUSIONS: Our results suggested that converting patients with gastrointestinal complaints from MMF to equimolar doses of EC-MMF reduced gastrointestinal-related symptom burden and frequency of stools.