Healthy bowel movements come in a wide range of colors, from different shades of brown to green, explains Mayo Clinic. The color of stool depends on the food the person ate and the amount of bile in his stool.
Changes in stool color may occur due to diet and medication, according to MedicineNet.com. Other potential causes of stool color change include illnesses such as diverticulitis, Chron's disease and gallbladder disease. It is important for patients to consult a health care professional if the color of their stool changes drastically, states Mayo Clinic. Red or black stool may be a sign of intestinal bleeding, while white or light-colored stool may indicate bile duct obstruction.