In some individuals, certain foods may irritate the intestines, leading to the occurrence of bloody stools. Underlying health conditions, such as inflammatory bowel disease (IBD), can cause bloody stool.

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

In some individuals, certain foods may irritate the intestinal lining, leading to inflammation and bleeding. This may occur if a person has an allergy to a specific food or beverage, such as milk or dairy products.

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 beets, can cause a person’s stools to have a reddish hue. This can cause stools to appear as though they contain blood.

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 involving 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

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

Some common symptoms of food poisoning include:

If a person experiences bloody diarrhea, they should consult a healthcare professional, as this is a sign of severe food poisoning.

Related foods

The following are some common causes of food poisoning:

  • uncooked foods 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, resulting in blood in the stool. 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:

Bloody stools can appear in different colors, depending on the location of the bleeding within the GI tract.

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

If the blood originates from higher up in the GI tract, a person may have blood mixed into their 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: Anal fissures are tears or open sores near the anus. A person may notice blood on the toilet paper when they wipe.
  • Hemorrhoids: Hemorrhoids are veins located around the anus that swell up, resulting in blood in the stool. 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
  • 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 the stools. In the case of cancer, stools may appear dark brown or black.

It is essential for a person to consult a doctor if they experience blood in their stool. The bleeding may not be due to anything serious, but it is important that a doctor determines 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 a particular type of food may be irritating the intestinal lining and causing bloody stools.

If a person is unsure whether their stools are appearing red or black due to food or another cause, it is best to consult a doctor for a checkup to determine 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:

Foods that cause a variety of digestive issues such as constipation or diarrhea may result in blood in the stool due inflammation of the GI tract.

The best way to tell the difference between blood or food, is to stop eating particular foods that may cause color changes and see if the blood in the stool continues.

The most common reason for bloody stools includes:

  • hemorrhoids
  • anal fissures
  • IBD or inflammation in the bowels
  • allergies

In some cases, having a food allergy or consuming foods that contain harmful bacteria can irritate the intestinal lining and may result in blood in the stool.

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.