Estimating the prevalence of gastrointestinal symptoms among patients with renal failure faces the same obstacles. Studies have been limited by non-standardized definitions of gastrointestinal symptoms and varying patient populations. The prevalence of gastrointestinal symptoms in patients with renal failure is thought to range from 70% to 79%. The prevalence of these disorders is generally similar in predialysis patients, patients on hemodialysis, and patients on peritoneal dialysis. but a trend towards increasing symptoms with increasing duration of renal failure exists. The prevalence of constipation is as high as 63% in patients on hemodialysis and 29% in patients on peritoneal dialysis, compared with a prevalence of 10–20% in the general population. Uremic retention molecules are a large group of molecules that accumulate in the gastrointestinal tract of patients with renal failure and are believed to contribute to the uremic syndrome. Uremic retention molecules produced by microbial metabolism may have a role in the morbidity and mortality associated with renal failure. A considerable pro portion of cases of renal failure can be attributed to diabetes mellitus, and as anorexia, nausea, and vomiting are common symptoms in patients with renal failure, the high incidence of gastrointestinal symptoms in patients with renal failure may be induced by gastroparesis. Esophagogastroduodenoscopy has been used to investigate the etiology and prevalence of such lesions. Although results from studies that have used this technique are conflicting, it seems that the frequency of upper gastrointestinal lesions in patients with renal failure is greater than in the general population. The prevalence of positive fecal occult blood test results in patients with CKD is estimated to be 19%. The most common site of upper gastrointestinal tract involvement is the duodenum, as duodenal lesions are found in 61% of ESRD patients with positive fecal occult blood tests