Objective: To observe the effect of coix seed diet therapy on the nutritional status of peritoneal dialysis patients and to discuss the potential reasons. Methods: 30 dialysis patients with regular return visit to peritoneal dialysis center of Guangdong Provincial Hospital of Traditional Chinese Medicine were recruited and divided into two groups according to their willingness. 13 patients in control group continued their usual dialysis prescriptions and medications, whereas 30 g of coix seed per day was added to the usual therapies of 17 patients in coix seed group. Changes in nutritional status of dialysis patients in two groups were evaluated after a 12-week treatment. Results: Two patients (one in each group) quitted the study because of pulmonary infection. After treatment, the nutritional parameters of serum albumin level (P = 0.004), total protein level (P = 0.008), and body mass index (P = 0.023) were increased significantly in coix seed group. And the statistical differences of serum albumin level and body mass index were significantly compared to control group (P = 0.008 and P = 0.032, respectively). Moreover, the C-reactive protein level had a significant decrease (P = 0.001) and the clinical symptoms of dialysis patients including tiredness, anorexia, xerostomia, and abdominal distension showed a significant improvement (P < 0.05) in coix seed group. And urinary volume of dialysis patients in coix seed group also had a significant increase (P = 0.027). However, there is no significant difference showed in control group. Conclusion: Coix seed diet therapy plays a rote in improving the nutritional status of peritoneal dialysis patients by relieving digestive tract symptoms, increasing urinary volume, and meliorating micro-inflammatory state. But as a pilot study, the results still need to be validated by further large-scale researches. (C) 2013 Elsevier Ltd. All rights reserved.