Undigested Food in Stool

Undigested Food in Stool

The intestine eliminates anything that is not absorbed during the digestion process through the faeces. It is therefore not infrequent that the presence of undigested food can be observed inside the latter. However, the digestive processes developed by the stomach and intestines should generally avoid this phenomenon. In this article, we will give you a complete guide about undigested food in stool.

Food in the stool should not alarm us much unless other intestinal symptoms also accompany it. In this case, contacting your doctor is the best thing to do to arrive at a diagnosis and resolve the underlying problem.

The presence of undigested pieces of food is caused by incorrect or absent chewing of food. In these conditions, it is difficult for the intestine to fragment the food into smaller pieces.

If this is your problem, I invite you to continue reading the article to find the right information to solve this problem.

When does undigested food appear in the stool?

The appearance of undigested food in the stool is not something that happens often. It cannot be called normal, and luckily, it rarely indicates serious problems. It has a close relationship with the type of food you eat. In fact, by limiting its consumption, the problem will tend to be solved.

Some foods are difficult to digest, especially those very rich in fibre, which are relatively resistant to stomach and intestine processes during food breakdown.

However, this should not prevent us from including a good dose of fibre in our diet as these, inside the stool, have the function of drawing water, making the faecal cylinder softer and more comfortable to expel. Threads are among the most important allies for intestinal health and the fight against constipation. A more bulky faecal mass stimulates peristaltic movements that make us remove stool faster.

We can discover corn, flax seeds, pumpkin seeds, sunflower seeds, and lentils, among the food traces we can find inside our faeces. Our body has all the enzymes available for breaking down various sugars, including starches, but cellulose is excluded from the list.

When the cause of undigested food in the stool is a specific part of the food itself, there is no reason to worry. The suggestion is to chew the food carefully. To reduce the particles’ size as much as possible and make them more accessible by digestive enzymes. Another tip is to consume cooked vegetables as much as possible to soften the fibres that can thus be digested—thus maximizing the number of nutrients absorbed.

When should you worry? And when not?

For all we have said so far, food in the stool should never be a cause for concern. But there are cases in which particular symptoms accompany this phenomenon, and for this reason. It would be good to report everything to your doctor to make sure that there is nothing serious.

The symptoms in question are:

  • persistent diarrhoea;
  • Excessive weight loss without a plausible explanation
  • Presence of blood in the stool
  • Frequency in defecation.

This last point is critical. As a too rapid intestinal transit means that the food remains for a short time available to the enzymes responsible for digestion. So it is straightforward to find it, then only partially digested in the faeces. This represents a problem because the nutrients necessary for the body to perform all its functions and obtain energy are not absorbed. The result is weight loss, a sense of weakness, lack of concentration and energy, anaemia.

All the symptoms listed can be a sign of pathologies, such as:

  • Crohn’s disease: an inflammatory condition that affects the intestines and causes a variety of problems often accompanied by pain;
  • Celiac disease: an autoimmune disease caused by a reaction by the body to gluten. A protein molecule found in some cereals, including wheat. Furthermore, in affected subjects, gluten represents a toxic molecule that creates even severe symptoms;
  • Irritable bowel syndrome: in this case, the bowel becomes particularly sensitive, even to sudden changes in temperature and periods of particular stress;
  • Lactose intolerance. Some people have a deficiency in an enzyme called lactase responsible for digesting lactose, a sugar found in milk. If present as it is, the latter is toxic for the intestine and causes painful colic, flatulence, and indigestion.

What to do?

When food in the stool is accompanied by one of the symptoms described above, it is best to contact your doctor to report all the signs to arrive at a diagnosis. Often, the first test to be prescribed examines the faeces and continues with other tests based on the response.

Also Read: Baking Soda For Heartburn

undigested food in stool: Blood 

The presence of blood in the stool is an expression of bleeding, more or less intense, which can occur in any tract of the digestive system:

  • oesophagus,
  • stomach,
  • small intestine,
  • large intestine,
  • straight,
  • Anal canal.

The presence of blood in the stool can be:

  • manifest (macroscopic), expression of intense bleeding, often acute, recognizable because the seats are dyed bright red, or take on a dark brown or black colour, or because of the isolated emission of blood;
  • occult (microscopic): expression of slight bleeding, more often chronic, not recognizable with the simple inspection of the feces, but detectable only with hazmat chemical tests of the feces (SOF = Occult Blood in the Feces).

Also Read: Symptoms Of Ear Infection

Causes of upper digestive bleeding

Esophageal pathologies

  • Esophagitis: Gastroesophageal reflux esophagitis is among the most frequent causes of EDS. The damaged esophageal wall of acidic gastric juices can bleed, often chronically, through the stomach, where the blood will be digested and then excreted in the stool, in a microscopic or macroscopic manner depending on the entity. (lazye.com)
  • Esophageal varices: these are dilations of the esophagus veins, mainly in patients with severe liver disease. Their lesion can lead to major bleeding, with the emission of blood from the mouth (haematemesis), or milder bleeding, with the emission of blood in the stool.
  • Esophageal tumours: benign lesions (polyps), or more frequently malignant (esophageal carcinoma), can bleed, usually mildly and continuously.
  • Mallory-Weiss syndrome: is a laceration of the lower part of the esophagus due to profuse vomiting, which can manifest itself with hematemesis or melaena.
  • Angiodysplasia and vascular ectasia: it is a malformation of the vessels of the esophageal wall, which makes them fragile and bleeding easily, more frequently causes mild chronic blood dripping.

Also Read: How To Buy an Electric Bike Online in 2021


  • Peptic ulcers: gastric ulcers are one of the most frequent causes of bleeding, most often presents itself as a chronic blood dripping, not macroscopically detectable in the stool. More rarely, there may be massive bleeding, which may present with hematemesis or melaena. (macarthurmc.com)
  • Acute gastritis: The stomach’s inflammation rarely presents with melaena, usually secondary to severe hemorrhagic gastritis (secondary to prolonged use of NSAIDs, or following burns and serious systemic diseases); more frequent is the presence of occult blood in the feces.
  • Chronic gastritis: Chronic inflammation of the gastric walls most frequently manifests itself as occult bleeding.
  • Gastric neoplasms: benign lesions (polyps), or malignant (more frequently), can bleed slowly and continuously, appearing as occult hemorrhages, more rarely as melena.
  • Hiatal hernia: the ascent of the stomach through the diaphragm can rarely cause occult bleeding.
  • Varices and gastric erosions are less frequent than esophageal varices and occur more frequently in patients with chronic alcoholic liver disease.

Also Read: Dry Mouth At Night


  • Duodenal ulcer: is one of the most common causes of upper hemorrhage, occurring more frequently as an occult hemorrhage, more rarely, in intense bleeding, such as hematemesis or melaena.
  • Duodenal tumours: benign (polyps) or malignant tumours can cause chronic bleeding.
  • Ampullary tumours: tumors, usually malignant, which have a high tendency to bleeding and which obstruct the outflow of bile, can cause the emission of acholic stools (without bilirubin) and mixed with blood, taking on a silvery appearance.
  • Hemobilia: communication is created between the biliary tract and the hepatic blood vessels, which can cause hematemesis or melaena.
  • Perforation of the duodenum by a gallbladder stone: can cause hematemesis or melaena.

Also Read: Different Types of Cancer

Causes of lower digestive bleeding

Small intestine

  • Intestinal tumours: Benign and malignant intestinal tumors are infrequent and are rare causes of digestive bleeding, most commonly occurring as occult bleeding.
  • Inflammatory bowel diseases: here, the most important inflammatory disease is Crohn’s disease, characterized by an infiltration of inflammatory cells into the intestinal wall, which damages it, causing ulcers. Which causes chronic microscopic bleeding. More rarely, there is an intense enterorrhagia.
  • Infectious diseases: Bacterial (most frequently), viral or parasitic infections can cause acute enterorrhagia.
  • Meckel’s diverticulum is an extra flexion of the intestinal wall, which derives from an embryonic structure. This regresses in the term newborn, but in some cases, it can persist and be the microscopic or macroscopic hemorrhage site.
  • Necrotizing enterocolitis: it is a neonatal pathology, which mainly affects premature babies, characterized by intestinal necrosis, and manifests itself with abdominal distension, possibly associated with enterorrhagia.
  • Intestinal infarction: the suffering of the intestinal wall, secondary to the reduced blood supply, is a rare cause of intestinal hemorrhage, especially in the elderly, which more frequently manifests itself as enterorrhagia.

Large intestine (colon)

  • Diverticulosis: is one of the most frequent causes of intestinal bleeding (not just EDI). It is a condition characterized by the presence of extroversions of the intestinal wall, especially in the last section of the colon, frequently asymptomatic or manifested by the presence of post-prandial abdominal pain (i.e., after eating). Digestive bleeding is usually mild and presents as occult bleeding, more rarely as enterorrhagia or hematochezia (in very low intestinal diverticula). Inflammation of the diverticula ( diverticulitis ) is a possible complication, which manifests itself as enterorrhagia.
  • Intestinal tumors: benign polyps (the most frequent) or malignant intestinal tumors (especially those located in the ascending colon). It can cause chronic blood dripping, not macroscopically detectable in the stool, which can cause the subject to become anemic.
  • Chronic inflammatory bowel diseases :
  • Crohn’s disease can be the cause of enterorrhagia or occult bleeding.
  • Ulcerative colitis, an inflammatory disease characterized by predominant rectal involvement and distal colon, often gives rise to massive bleeding, which may occur as enterorragia, hematochezia, or hematochezia.
  • Infectious diseases: bacterial colitis (mainly), viral or parasitic, can manifest itself with a profound painful abdominal symptomatology associated with mucus-bloody diarrhea. The most frequent bacterial etiologic agents include enterohemorrhagic E. coli, Shigella dysenteriae, Clostridium perfringens, Clostridium difficile. Among the protozoal forms, Entamoeba histolytica is the most frequent; viruses rarely lead to bloody diarrhea (dysentery),
  • Angiodysplasia,
  • Intestinal infarction

Undigested Food in Stool: Symptoms

The emission of blood in the feces can manifest itself clinically in a different way depending on the entity and therefore be classified as

  • microscopic,
  • macroscopic,

and where it occurred (lower or upper digestive hemorrhage):

  • melena,
  • enterorrhagia,
  • hematochezia,
  • Also, it can present itself in a manner
  • isolated,
  • in association with other signs or symptoms.

It is essential to pay attention to the associated symptoms because these can orient the diagnostic question towards a particular pathology:

  • Vomiting: it can accompany upper digestive bleeding, especially in the case of ulcers, and it can have a dark color (like the laying of coffee) due to the presence of digested blood.
  • Epigastric burning, difficulty in swallowing: may be associated with gastroesophageal reflux esophagitis.
  • Epigastric pain when fasting or after meals: can be associated with a peptic ulcer.
  • Abdominal pain crampy: may be associated with diverticular disease (more frequently) or chronic inflammatory diseases, infectious diseases, or intestinal cancers.
  • Constipation of recent onset: it can be an expression of intestinal neoplasms or a diverticular pathology.
  • Diarrhea: it can be the expression of an infectious or inflammatory pathology of the intestine or a neoplasm.
  • Fever: it can occur in infectious or inflammatory bowel diseases or neoplasms.
  • Anal pain: So, it is very indicative of the presence of a fissure or the haemorrhoidal pathology.
  • Anal itching or foreign body sensation: can be strongly indicative of haemorrhoidal disease.

In particular, it is essential to pay attention to the warning signs and symptoms:

  • anemia,
  • asthenia,
  • weight loss,
  • recent constipation or diarrhea,

Undigested Food in Stool: Diagnosis

Suppose the emission of blood is macroscopically detectable. The naked eye observation of a fecal sample is sufficient for the diagnosis.

History: it is essential to collect relevant information

  • associated symptoms,
  • So, pre-existing pathologies (for example, liver cirrhosis can direct the diagnosis towards varicose hemorrhage),
  • family history, especially for neoplastic or inflammatory pathologies, for which there may be familiarity.

Physical examination: So, it is essential to detect

  • the general state of health of the subject,
  • regions of abdominal pain,
  • abdominal masses,
  • anal alterations (fissures, hemorrhoids) are necessary when the patient complains of proctorrhagia.

Coproculture and physicochemical examination of feces: this is an examination that involves the collection of a fecal sample.

Colonoscopy: So, the exploration of the whole colon. Using a flexible tube introduced via the anus is essential for identifying the intestinal wall (neoplasms, diverticula, inflammatory pathologies).

Gastroscopy: involves the insertion of a flexible tube through the mouth. To explore the upper digestive tract up to the duodenum and identify esophagitis, gastritis, peptic ulcers.

Blood sampling: it is useful for evaluating

  • complete blood count and any associated anemia,
  • So, inflammatory markers (ESR, CRP), to detect inflammatory or infectious diseases,
  • tumor markers, if elevated, can be a sign of a neoplasm.

If these investigations are not sufficient to identify the cause.


Please enter your comment!
Please enter your name here