Foods That Can Cause Bloody Stools (Or Appearances Of)

January 9, 2026 •

6 min read

According to Healthline, while no food inherently causes bloody stools, certain items and irritants can trigger gastrointestinal distress or mimic the appearance of blood. This article explores what foods can cause bloody stools or, more commonly, simply stain your stool a concerning color.

Quick Summary

Certain foods, food dyes, and medications can alter stool color, making it appear red or black, which may be mistaken for blood. True bloody stools are caused by medical conditions, with foodborne illnesses and spicy foods being potential triggers for bleeding via irritation. Consulting a doctor is crucial if you are concerned.

Key Points

Food vs. Bleeding: Beets, red food dyes, and blueberries can cause harmless, temporary changes in stool color that mimic blood. True bloody stools result from an underlying medical issue.
Red Stool Culprits: Natural pigments from beets (betalain) and tomatoes (lycopene), along with artificial red dyes, are common causes of reddish-looking stool.
Black Stool Triggers: Dark-colored foods like black licorice and blueberries, as well as medications like iron supplements and Pepto-Bismol, can lead to black or tarry-looking stool.
Food-Induced Bleeding: Food poisoning from contaminated food can cause serious bloody diarrhea, and spicy foods can irritate the digestive tract, potentially leading to bleeding from fissures.
When to See a Doctor: Persistent discoloration, accompanied by symptoms like pain, fever, or fatigue, requires medical evaluation to rule out serious conditions like IBD, ulcers, or colon polyps.
Color Clues: The color of actual blood provides clues about its source: bright red for lower GI bleeding (e.g., hemorrhoids), and dark or black for upper GI bleeding (e.g., ulcers).
Medication Effects: Beyond food, common over-the-counter medications like iron supplements and bismuth-containing antacids are known to discolor stool.

Distinguishing Food-Induced Color Change from Actual Blood

Noticing a change in stool color can be alarming. However, it is essential to distinguish between a color change caused by food and actual blood. Stool that appears red, maroon, or black can sometimes be attributed to diet, a harmless phenomenon that resolves on its own. In contrast, true bloody stools result from underlying health conditions affecting the gastrointestinal (GI) tract.

Foods and Substances That Can Change Stool Color

Several dietary items contain potent pigments or compounds that are not fully digested or absorbed by the body, leading to a startling, yet temporary, change in stool color.

Common culprits for red or reddish stool include:

Beets: The red pigment in beets, called betalain, is not always fully broken down by the digestive system and can turn stool a reddish-pink color. This is a harmless phenomenon known as beeturia.
Red Food Coloring: A wide variety of processed foods and drinks, from red-frosted cakes to sports drinks and red-colored cereals, contain artificial red dyes that can pass through the digestive system and stain the stool.
Tomatoes and Tomato Products: The red pigment lycopene found in tomatoes is sometimes not fully metabolized, especially when consumed in large quantities via juice, soup, or sauces.
Cranberries: Similar to beets, the powerful pigments in cranberries can sometimes cause a reddish appearance in stool.
Rhubarb: This vegetable is also known to cause a reddish color in stool due to its pigments.

Foods and substances that can cause dark or black stool:

Black Licorice: The black dyes and components in licorice can create a dark, tarry appearance in stool.
Blueberries: The deep purple and blue pigments in blueberries can cause dark-colored stool.
Iron Supplements: Oral iron supplements are a well-known cause of black stools.
Medications with Bismuth: Over-the-counter stomach remedies like Pepto-Bismol contain bismuth subsalicylate, which interacts with trace amounts of sulfur in the GI tract to produce black stools.

Food-Related Conditions That May Trigger Real Bleeding

While the foods listed above typically cause false alarms, certain food-related issues can lead to actual bleeding in the GI tract.

Food Poisoning: Infections from harmful bacteria such as E. coli, Salmonella, or Campylobacter can cause severe gastrointestinal inflammation and bloody diarrhea. This is a serious condition that requires medical attention.
Spicy Foods: Capsaicin, the compound that gives chili peppers their heat, can irritate the digestive tract. In some sensitive individuals, this can lead to severe diarrhea and, in turn, cause or worsen anal fissures, resulting in bright red blood on toilet paper or in the bowl.
Milk Allergy (Especially in Infants): A food allergy, such as a milk or dairy allergy in infants, can cause inflammation and bleeding in the intestines.
Exacerbating Existing Conditions: For individuals with inflammatory bowel diseases (IBD) like Crohn's disease or ulcerative colitis, certain food triggers (such as spicy, fatty, or high-fiber foods) can worsen symptoms and lead to bloody stools.

Comparison: Food Discoloration vs. Medical Bleeding


Characteristic	Food Discoloration	Medical Bleeding	Action Required
Appearance	Color changes due to diet are often consistent and uniform. The color may be red, maroon, or black, but often without the other signs of distress.	Bright Red Blood: Often indicates bleeding in the lower GI tract (rectum, anus) from issues like hemorrhoids or fissures. Dark or Tarry Stools (Melena): Suggests bleeding higher up in the GI tract (stomach, esophagus), where blood has been partially digested.	Monitor. If other symptoms or persistence occurs, see a doctor.
Associated Symptoms	Typically none, or only minor digestive upset related to the food itself.	Often accompanied by: Abdominal pain, cramping, dizziness, fatigue, fever, unexplained weight loss, or changes in bowel habits.	Seek medical advice. The presence of other symptoms is a strong indicator of a medical issue.
Duration	The color change is temporary and should resolve within a day or two after the food is eliminated from the diet.	Persistent, recurring, or worsening symptoms indicate an ongoing problem that requires diagnosis and treatment.	Seek medical advice. If symptoms persist beyond 48 hours or worsen.
Confirmation	The color change disappears when the offending food is no longer consumed.	Can be confirmed by a fecal occult blood test or diagnostic procedures like a colonoscopy or endoscopy.	Medical testing. A doctor can confirm the presence of blood and its source.

Conclusion: When to Seek Medical Attention

In many cases, seeing a red or black stool is a harmless result of recent dietary choices, such as eating beets, blueberries, or foods containing red dye. If you suspect food is the cause, monitoring your stool color after eliminating the suspicious food is a simple way to test your theory. The color should return to a normal brownish hue within a day or two.

However, it is crucial to remember that blood in the stool is never normal. Any persistent change in stool color, especially when accompanied by other symptoms like abdominal pain, fever, fatigue, or significant changes in bowel habits, warrants a consultation with a healthcare professional. Conditions like hemorrhoids, anal fissures, infections, inflammatory bowel disease, and, in rare cases, colon cancer can cause bloody stools, and require a proper diagnosis and treatment. Do not hesitate to seek medical advice to rule out a more serious underlying issue.

For more information on digestive health, you can consult reliable sources such as the National Institute of Diabetes and Digestive and Kidney Diseases at NIDDK.gov.

Recognizing True Bloody Stools

What does real bloody stool look like?

Bright Red Blood: Usually indicates bleeding from the lower GI tract, such as the colon, rectum, or anus. It can appear mixed with stool, on its surface, or on the toilet paper.
Dark Red or Maroon Stools: Suggests bleeding further up in the colon or small intestine.
Black, Tarry Stools (Melena): Often signifies bleeding in the upper GI tract, like the stomach or esophagus. The blood turns black and tarry after being digested.

Other possible causes of bloody stools

Hemorrhoids: Swollen veins in the anus and rectum that can bleed during bowel movements.
Anal Fissures: Small tears in the lining of the anus, often caused by passing hard stools.
Diverticulosis/Diverticulitis: Small pouches that form in the colon wall can bleed or become inflamed.
Infections: Bacterial infections from contaminated food can cause bloody diarrhea.
Inflammatory Bowel Disease (IBD): Chronic inflammation of the digestive tract in conditions like Crohn's disease and ulcerative colitis.

How is bloody stool diagnosed?

Physical Exam: A doctor will perform a physical examination, potentially including a digital rectal exam, to check for issues like hemorrhoids or fissures.
Lab Tests: Stool samples can be tested for the presence of hidden blood (fecal occult blood test).
Endoscopy or Colonoscopy: These procedures involve inserting a scope with a camera to view the upper or lower GI tract and identify the source of bleeding.

What to do if you suspect bloody stools

Consider recent diet: Review what you have eaten in the past 24-48 hours. If you ate something known to cause color changes, wait to see if the stool color returns to normal.
Note other symptoms: Keep track of any other symptoms such as pain, fever, or changes in bowel habits to discuss with a doctor.
Seek medical advice: If the stool color does not normalize, or if you experience any concerning symptoms, contact a healthcare professional for a proper evaluation.

Can stress cause bloody stools?

Indirectly: While stress itself doesn't directly cause bleeding, it can exacerbate conditions like IBD or irritable bowel syndrome (IBS), leading to changes in bowel habits and potential irritation that could cause bloody stools.

Are all types of spicy foods dangerous?

Individual sensitivity: The effect of spicy foods varies by individual. For people without GI conditions, they are generally harmless, but for those with sensitive digestive systems, they can cause irritation.

Can certain medications be a factor?

Yes: Besides bismuth and iron supplements, certain medications like NSAIDs (e.g., ibuprofen, naproxen) and blood thinners can cause GI bleeding.

Can constipation lead to bloody stools?

Yes: Straining to pass hard stools can lead to small tears (anal fissures) or aggravate hemorrhoids, causing bright red blood on the stool or toilet paper.

Frequently Asked Questions

Yes, several foods and drinks can temporarily change the color of your stool. Items containing red dyes (like Jell-O or red candy), beets, tomatoes, cranberries, black licorice, and blueberries are common culprits for reddish or blackish stool.

If the color change is due to food, it will be temporary and will usually resolve within a day or two after you stop eating the item. Real blood often presents with other symptoms like abdominal pain, fever, or dizziness. Bright red blood typically indicates a lower GI issue, while black, tarry stools suggest an upper GI problem.

Spicy foods, particularly those with capsaicin, can irritate the digestive tract and cause severe diarrhea in some people. This, in turn, can lead to irritation or small tears in the lining of the anus (fissures), causing bright red blood on the toilet paper.

Yes, food poisoning caused by bacteria like E. coli or Salmonella can lead to severe gastrointestinal inflammation and cause bloody diarrhea. This requires medical attention.

Certain medications, most notably iron supplements and bismuth-containing products like Pepto-Bismol, are known to turn stools black or dark.

Causes range from less serious issues like hemorrhoids and anal fissures to more serious conditions such as inflammatory bowel diseases (Crohn's, ulcerative colitis), diverticulitis, polyps, and GI bleeding from ulcers or cancer.

Any amount of blood in the stool is not normal and should be evaluated by a healthcare professional, especially if it persists, is heavy, or is accompanied by other symptoms. It's always best to seek a professional diagnosis to rule out serious issues.

In infants, a milk allergy or intestinal infections can cause bloody stools. While constipation is a common cause of small amounts of blood, any observation of blood in an infant's stool warrants a call to their pediatrician.