Stool color is a topic you may be hesitant or embarrassed to discuss with your healthcare provider. Most people have what they consider to be a range of normal stool colors. But when things look different, you may worry that it’s a sign that something is wrong. A wide range of factors can contribute to discolored stools, though, including eating red licorice.
Red Stools
From time to time, you may notice your stools contain bright red matter. According to telehealth provider Hello Pediatrics, most of the time, red fecal matter isn’t blood. It’s usually food, particularly foods that use red food dye, like licorice. Fruits and vegetables can also be the culprit — tomatoes, beets, red peppers, rhubarb, and cranberries are also known to be a cause.
Some medications can also cause red discoloration, according to HealthPartners, a healthcare system in Minnesota. Antibiotics including cefdinir can create harmless red stools, but this class of drugs can also cause intestinal bleeding. So, call your doctor right away if you have red stools while taking antibiotics.
Medical reasons for red or bloody stools include hemorrhoids, which are swollen veins in the rectum or anus. Constipation can also cause swelling and tears that lead to blood in your fecal matter, as can chronic diarrhea. Anal fissures, or tears in the skin around the anus, are another possibility. All of these conditions can be easily treatable. But you should still confirm diagnosis with your doctor to make sure you don’t have a more-urgent medical issue.
Other potentially serious medical conditions can cause red or bloody stools. These include anal abscesses (pus-filled glands) and fistulas such as peri-anal fistulas (a tunnel from the end of your anus to the skin around your anus), which can occur with infections of the anal glands as well as with inflammatory bowel disease (IBD). Other conditions of the lower digestive tract may also cause red blood in stool, according to Cleveland Clinic.
Bleeding anywhere in your digestive tract can be alarming, and it merits a trip to your physician for proper diagnosis. Get emergency medical care if you notice:
- A lot of blood
- Abdominal cramping
- Weakness or fatigue
- Dizziness
- Rapid pulse or breathing
Black Stools
Most commonly, black or dark-colored feces can be the result of your diet and lifestyle. Taking iron supplements, bismuth subsalicylate (Pepto Bismol), activated charcoal, or eating certain foods may cause you to pass black stools.
Foods that can cause black fecal matter include those that use dark food coloring or are naturally dark, such as black licorice, chocolate, and blueberries, according to Cary Gastroenterology in the Raleigh-Durham area of North Carolina.
Black stools that are iron- or diet-related are not a cause for concern. If you’re taking bismuth subsalicylate frequently for an undiagnosed condition, see your doctor to make sure the underlying issue isn’t causing bleeding that’s contributing to the discoloration.
Black stools can also indicate bleeding in the upper section of the digestive system, such as the stomach, esophagus, and upper small intestine, according to Cleveland Clinic. Common causes include peptic ulcers, severe inflammation of the stomach or esophageal lining, and cancer, among others. These require medical attention.
Call your doctor to make an appointment if you suspect bleeding is the cause. Call 911 or go to the emergency room if you:
- Are vomiting blood or what looks like black coffee grounds
- Are feeling dizzy or weak
- Have had several days of black stools
- Are getting heart palpitations or shortness of breath
Green Stools
Green-tinged feces is not uncommon, according to Northwestern Medicine. And it, too, can have a number of causes. As with black and red stools, diet can be the culprit here. Green and blue food dyes, leafy green vegetables, matcha, blackberries, and blueberries can all lead to green or very dark green fecal matter. Iron supplements and bismuth subsalicylate (Pepto Bismol) can also turn feces dark green rather than black. Antacids containing aluminum hydroxide (Gaviscon, Maalox, Mylanta) and certain antibiotics can also produce green stool.
Both bacterial (salmonella, E. coli) and viral (norovirus, or stomach flu) infections can cause green feces. A change in the flow of bile, a yellow-green digestive fluid, can also cause it. If bile moves too quickly through the digestive system, like when you have diarrhea, it may still come out green.
If you’re on a keto diet or you’re otherwise ingesting large amounts of fats, your liver produces more bile to break down all the fat, which can also make your stool green. Gallbladder removal will cause bile to flow directly from your liver to your small intestine, which can temporarily change the color of your feces.
While green stools are often harmless, contact your doctor if you also have:
- Severe abdominal pain and cramping
- Fever
- Severe, chronic diarrhea
- Weight loss
- Dehydration
Digestion Takes Time
Understanding the basics of digestion can help you determine if licorice is a factor in your unusual stool color. The food you eat stays in your stomach and small intestine for an average of six hours after you have eaten before it moves to your large intestine, according to Mayo Clinic. While the food is there, it’s broken down by digestive fluids into a nutrient-rich mixture.
Once it reaches your large intestine, also called your colon, the food’s nutrients and water are absorbed. And the undigested matter — the waste — dries out as it moves through. It takes an average of 36 to 48 hours for this to happen, before it’s passed as stool.
If you’re worried about your stool color, keep track of when you ate licorice to determine whether it’s the culprit. If the timeline doesn’t match, or if you suspect any of the other aforementioned reasons for the discolored fecal matter, contact your doctor or get emergency attention, depending on your situation.
