What could be the cause of yellow stools?

Change in bowels: The amount, color, frequency of stool varies with foods, speed of emptying of the GI tract, medications & supplements ingested, gut flora (unique for each individual), additives (like blood), subtractions (like absent bile), infection, inflammation, & other factors. If stool pattern has changed, is unusual for you, & the change persists, or is accompanied by other symptoms, see your doctor.

A # of reasons: Hello. Yellow stool, especially if light in color can be caused by problems with the liver or gallbladder. Gastroesophageal reflex, celiac disease and malabsorption can also be causes. I recommend that you contact your physician so that this can be explored.