Can Tomato or Vegetable Juice Change a Bowel Movement to Red?

Certain foods and juices with strong colors can change your bowel movements to red.

If you're not expecting to see such a change, it can make for quite a shock when you look in the toilet bowl. But while stool that appears red can signal a health problem, in many instances it is a harmless side effect of eating red foods such as tomatoes, according to Cleveland Clinic.

Red Stool, But Not Blood

Tomatoes and some vegetables contain strong pigments in their flesh. In tomatoes, the pigment is the carotene known as lycopene, whereas vegetables such as beets contain betanin. In both cases, the pigment stays mostly intact during the digestion process. This colors the mass of broken-down food and waste that make up stool, so your bowel movement looks red.

You might even notice small red pieces of tomato in your stool.

Similarly, beta-carotene in carrots may turn your waste orange, though this is more common in people who drink large amounts of carrot juice, according to Cleveland Clinic.

Artificial food coloring, commonly used in popsicles and drink mixes, can also change the color of stool to red, among other colors, according to Mayo Clinic.

Red Stool May Be More Common in Babies

A baby's digestive system is immature, so foods can't be broken down well. That's why parents slowly wean babies on to solid foods. During weaning, juiced or mashed vegetables are commonly used.

According to Seattle Children's Hospital, 90 percent of red stools in children are not caused by blood. Red dye in beverages, candy, and cereal are often the culprit. Foods such as beets, cranberries, red peppers, rhubarb, and tomatoes are also to blame.

Consider the Fiber Content

Fiber is an important carbohydrate that impacts the digestive system and promotes intestinal gut health, according to Mayo Clinic.

Tomato and vegetable juices can contain a lot of dietary fiber, particularly if the juice is pulpy and thick. Fiber helps bowel movements by bulking stools into moist, firm shapes that pass easily.

In some people, however, such as those with irritable bowel syndrome, very high fiber can cause digestive irritation. That means more partially digested food, such as tomato skin and beet fragments, which could make your stool look even redder.

When to See a Doctor

A change in bowel movement color soon after drinking tomato or vegetable juice isn't too much of a concern. But if these foods haven’t been in your diet recently, a change in stool color could signal an underlying issue, such as hemorrhoids, anal fissures, inflammatory bowel disease, and even certain cancers, according to Harvard Health Publishing.

If you notice that your bowel movements stay red for several days, experience tarry stool, or have pain when on the toilet, speak to a doctor.

Similarly, if stools become very foul-smelling or very watery, you may have a bowel infection or more serious complication. If these symptoms stay around for a week or more, ask your doctor for advice.