Causes for yellow stool with an assortment of undigested food in it. Also very soft and unformed.

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.