A healthy stool is usually solid, soft, and brown. While diarrhea is unpleasant, it is not usually a sign of something serious. Red or bloody diarrhea, however, may be a sign of an underlying health problem.
Diarrhea occurs when digested food material and water pass through the intestines too quickly. Instead of having time to form a solid mass, the material passes through in a liquid form.
Red diarrhea may be alarming, but stool color can help a person determine the cause of their symptoms. In this article, we look at the possible causes and treatment, as well as what other stool colors mean.
Six causes of red diarrhea:
- Dysentery: Diarrhea with blood is called dysentery. The most common causes of dysentery are Shigella bacteria or Entamoeba histolytica, a type of parasite. These can cause severe infections that inflame the intestines enough to result in bleeding.
- Red foods: Foods that are naturally red or contain red food coloring can turn the stool red. Red diarrhea might occur if the food that a person eats causes food poisoning or irritates the stomach. Foods that can turn stool red include beets, cranberries, red candy, red frosting, red licorice, tomatoes, and tomato sauce.
- Gastrointestinal (GI) bleeding: A range of conditions can result in GI bleeding, including colon polyps, inflammatory bowel disease (IBD), or gastric cancer. These conditions can cause significant blood loss that may turn diarrhea red.
- Hemorrhoids: Hemorrhoids are swollen blood vessels that occur inside the rectum and anus. They are a common cause of rectal bleeding and red diarrhea.
- Medications: The side effects of some medications may cause red stool. They can also irritate the stomach and potentially lead to diarrhea. Medications that cause red stools include liquid antibiotics.
- Anal fissure: Sometimes a scratch in the rectal area called an anal fissure can cause the stool to appear bloody. In this case, it may only be a small amount of bright red blood.
Other stool colors
Looking at stool color can often help a person determine what is causing their gastrointestinal symptoms.
Stool can come in a range of colors and have a variety of causes:
- Black stools: Tarry, black stools or stools the consistency of coffee grounds can indicate potential gastrointestinal (GI) bleeding. Black diarrhea can sometimes point to an upper GI bleed because the blood has had more time to travel through the GI tract and darken. Certain foods, such as licorice or high quantities of grape juice, may also turn stool black.
- Green stools: Green stools may be due to the presence of bile in the stool. Taking iron supplements can also cause stool to become dark green.
- Pale stools: Pale or clay-colored stools may indicate stones in the bile duct that empty from the gallbladder. If a person observes dark urine as well, this is a further sign that the gallbladder or liver could be the underlying cause. Some antacids that contain aluminum hydroxide can also cause pale stools.
- Yellowish, greasy stool: Yellow stool may be a sign of an infection or a malabsorption disorder, such as celiac disease.
When a person has diarrhea, they can lose a significant amount of fluid via their stool. When this happens, a person can become dehydrated.
A person should drink small sips of water or an electrolyte-replacement beverage regularly to help replace the lost water.
Diarrhea is often a way in which the body gets rid of an unwanted virus. Instead of prescribing medications that would slow the intestines and cause the body to retain the bacteria for longer, doctors may encourage a person to allow the diarrhea to run its course.
However, prolonged diarrhea may require additional treatments, such as intravenous fluids and medications to reduce cramping in the bowels.
In more severe cases of dysentery, a person may be given antibiotics or amoebicidal medications, or both if the exact cause is unknown.
If a person’s red diarrhea is due to GI bleeding, they may require a blood transfusion until the body can produce more blood. This procedure takes place in the hospital, and the person will need to remain there until their blood count is within a normal range.
If a person thinks red diarrhea is due to their medication, they should speak to a doctor about possible alternatives.
If red diarrhea is the result of dysentery or infection, a person can take steps to prevent it in the future.
Ways to help prevent red diarrhea include:
- Thoroughly cleaning all food preparation areas.
- Cooking foods thoroughly, as raw foods are more likely to carry Shigella bacteria.
- Drinking bottled or boiled water when traveling to a foreign country.
- Avoiding sexual contact with a person with an active shigellosis infection or who has recently been ill with the Shigella virus.
- Not swallowing water used for recreational purposes, such as water from a lake or river.
- Washing hands frequently with soap and water, especially after touching contaminated surfaces or changing a diaper.
- Avoiding food dyes known to cause red diarrhea can also help to keep this symptom at bay.
When to see a doctor
Bloody diarrhea may be a sign of a medical emergency, so a person should see a doctor as soon as possible.
A person should also see a doctor if they have the following symptoms in addition to red diarrhea:
- diarrhea that lasts more than 2 weeks
- a fever that is 101°F or higher
- severe diarrhea that lasts longer than 2 days
- pain or cramping that gets worse with time
While diarrhea is not always a cause for concern, severe or persistent bleeding may be a medical emergency. Anyone who is concerned about their red stool should speak to a doctor as soon as possible.