This study was designed to evaluate the curative effect of conversion from mycophenolate mofetil (MMF) to enteric-coated mycophenolate sodium tablets (EC-MPS) and its safety. One hundred and twenty renal transplant recipients who developed MMF-associated chronic diarrhea were selected as research subjects and treated with EC-MPS. The patients were followed up for 12 months to compare the improvement of gastrointestinal symptoms and the indexes such as carbon dioxide combining power (CO2CP), serum sodium, serum potassium, serum creatinine (Scr) and 24-h urine protein before and after conversion treatment. One hundred and ten of the 120 patients tolerated the conversion treatment and the dose increment of EC-MPS at week 28. After initiating the conversion treatment, the improvement rate of diarrhea within 2 weeks was 95% (114/120). Indexes, such as CO2CP, serum sodium, serum potassium, after conversion treatment were higher than those before treatment (P less than 0.05). No acute rejection reactions were observed in the 12-month follow-up. Indexes of Scr and 24-h urine protein had significant improvement after conversion treatment compared to before conversion treatment (P less than 0.05). Compared to before treatment, the average values of indexes in gastrointestinal symptom rating scale in the 12th month remained stable, except for the increase of dose. For renal transplant recipients who received suboptimal EC-MPS treatment due to gastrointestinal symptoms, conversion from MMF to EC-MPS can significantly lower gastrointestinal symptom load, improve quality of life, relieve electrolyte disturbance and improve the injured functions of transplanted kidney, without increasing the risks of acute rejection reactions.