In some people, certain foods may irritate the intestines, which can cause bloody stools. In other cases, underlying health conditions, such as inflammatory bowel disease (IBD), can cause blood in the stool.

Certain foods, such as beetroot, can also cause stools to appear red, which is harmless. Certain medications, food poisoning, and food allergies may also lead to blood in the stools.

This article looks at whether or not foods can trigger bloody stools, some conditions that can cause blood in stools, and other reasons that stools may contain blood or appear red.

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In some people, certain foods may irritate the lining of the intestines, leading to inflammation and bleeding. This may happen if a person has an allergy to a specific food or beverage, such as milk or dairy.

An existing medical condition, such as IBD, may cause irritation and inflammation in the intestines, and certain foods may trigger or worsen symptoms, such as bloody stools.

Some foods, such as beetroot, can lead to a person’s stools having a reddish hue. This can cause stools to appear as though there is blood in them.

Learn more about why beetroot turns urine and stools red here.

Having an allergy to milk can cause hives, stomach upset, and blood in stools — particularly in infants.

Trigger foods and beverages include anything containing milk, so a person may wish to avoid all dairy products and products containing milk proteins.

Crohn’s disease and ulcerative colitis are both types of IBD.

Ulcerative colitis is a condition of inflammation and ulcers in the intestines, which can cause blood in the stools. Crohn’s disease refers to chronic inflammation of the gastrointestinal (GI) tract that can also lead to rectal bleeding.

Related foods

Some foods can worsen IBD symptoms, resulting in blood appearing in the stools.

Trigger foods for IBD symptoms may include:

  • sources of hard-to-digest insoluble fiber, such as raw cruciferous vegetables, whole nuts, and whole grains
  • lactose
  • sugary foods
  • fatty, greasy, or fried foods
  • spicy foods
  • alcohol and caffeine

A 2015 article notes that certain non-absorbable sugars — such as sorbitol, mannitol, maltitol, and xylitol — can also trigger IBD symptoms.

Food poisoning occurs when a person contracts an infection after consuming contaminated foods.

Some common symptoms of food poisoning include:

If a person experiences bloody diarrhea, they should contact a healthcare professional, as this is an indication of severe food poisoning.

Related foods

The following are some common causes of food poisoning:

  • foods that are not cooked after a person has handled them, such as sandwiches and sliced meats
  • raw or undercooked shellfish
  • raw or undercooked ground beef
  • poultry
  • raw or undercooked chicken
  • eggs
  • unpasteurized milk
  • raw fruits and vegetables
  • unsafe water
  • improperly canned food
  • fermented foods that are typically homemade

Certain parasites can infect the intestines, leading to blood in the stools. Shigella bacteria can cause shigellosis, which is an infection that can cause bloody diarrhea, fever, and stomach cramps.

Related foods

Shigella can pass on through certain foods:

  • if someone with shigellosis is preparing the food
  • if foods are raw, as these are more likely to have Shigella bacteria
  • if fruits and vegetables are grown in fields with human waste contamination

Some foods and beverages can make stools appear red or black, such as:

It is also normal for stools to change color when a person is taking iron tablets or bismuth, which may darken stools.

Bloody stools can appear as different colors, depending on where in the GI tract the bleeding has come from.

For example, if a person has bleeding from the rectum or lower colon, they may see bright red blood coating the stools or mixed within stools.

If the blood is from higher up the GI tract, a person may have darker blood mixed into the stools, or the stools may appear black or tarry.

People may also have other symptoms alongside GI bleeding, such as bright red blood in the vomit or vomit that looks like coffee grounds.

A person may notice blood in their stools as a result of the following:

  • Anal fissures: These are tears or open sores near the anus. A person may notice blood on the toilet paper when they wipe.
  • Hemorrhoids: These are swollen veins around the anus, and they can result in blood in the stools. Severe constipation can lead to hemorrhoids. Following a high fiber diet and maintaining optimal hydration can help reduce the risk of developing constipation. People should aim to consume foods that are high in fiber if hemorrhoids appear due to chronic constipation. Some foods to limit or avoid include:
    • cheese
    • ice cream
    • fast food
    • chips
    • meat
    • processed foods
  • Diverticulitis: This refers to the inflammation of pouches in the wall of the colon, and it can cause GI bleeding. Most people with diverticulitis do not need to avoid any particular foods. In the past, people thought that nuts, popcorn, and seeds could worsen the symptoms. However, the National Institute of Diabetes and Digestive and Kidney Diseases suggests that these are not harmful to people with diverticulitis. A diet high in red meat may increase the chance of developing diverticulitis.
  • Colon polyps: Colon polyps are growths on the rectum or colon lining, and they can also cause GI bleeding. Foods that may increase the risk of colon polyps include fatty and fried foods, red meat, and processed meat.
  • Cancer: Bowel, colon, or rectal cancer can cause blood to appear in stools. In the case of cancer, stools may appear dark brown or black.

Learn more about bloody stools and potential causes here.

It is important for a person to contact a doctor if they have blood in their stools. The bleeding may not be due to anything serious, but it is important that a doctor finds out the source and cause of the bleeding.

If a person thinks that a certain food or beverage is triggering their symptoms, it may be helpful to keep a food diary and track symptoms. This can help a doctor determine whether or not a type of food may be irritating the intestinal lining and causing bloody stools.

If a person is not sure whether their stools are appearing red or black due to food or another cause, it is best to contact a doctor for a checkup to find out the exact cause.

In the case of severe and sudden bleeding, a person needs medical help straight away. A person also needs emergency help if they go into shock, which can cause the following symptoms:

In some cases, having a food allergy or eating foods that carry harmful bacteria can irritate the lining of the intestines and may result in blood in the stools.

A number of medical conditions, including IBD and colon polyps, can affect the GI tract and cause bloody stools.

If a person has a condition that can cause blood in the stools, they may need to avoid certain foods and beverages that could aggravate the condition and worsen their symptoms or bleeding. People can discuss suitable nutrition plans with a healthcare professional.