Normal stool colours include all brown shades and also green. Stool colour may change colours depending of what foods have been consumed and how much bile is present in the stool. The Mayo Clinic says that only rarely does bile colour indicate a serious medical condition.
The most common condition that may cause stool to appear yellowish is coeliac disease, a condition that occurs when the body has an immune response to gluten. Gluten is a protein found products containing wheat, rye or barley. Coeliac disease is diagnosed using endoscopy exams and blood tests.
Other possible causes of yellow or pale coloured stool can stem from malabsorption or the gallbladder, bile ducts, liver and pancreas.
Stool colour may change from time to time without a medical cause. However, if stool colour remains consistently pale or yellow for several days, you should consult your doctor.
A physician may need to perform blood tests and conduct a stool sample analysis to determine if an underlying condition is causing the yellowish-brown stool colour. An endoscopy or colonoscopy can check for digestive disorders.
Treatments depend upon what condition is causing the stool discolouration. If coeliac disease is the cause, your doctor probably will recommend a gluten-free diet.