bowel health

Chronic diarrhea: diagnosis, treatment, diet


Like any disease or disorder, the diagnosis of chronic diarrhea begins with the anamnesis, or with the collection of symptoms reported by the patient. Here, the physician will first have to understand what the patient means when he claims to be suffering from "chronic diarrhea", given that each of us has a subjective conception of his own intestinal activity.

Once the disorder has been ascertained, the doctor will have to investigate the underlying cause, asking precise questions about the frequency of daily evacuations, consistency of the fecal mass, stool volume, duration of the disorder and, clearly, on the presence of any accompanying symptoms.

Of course, a stay in tropical countries widens the spectrum of chances that chronic diarrhea is closely linked to a gastrointestinal infection. However, this does not exclude the possibility that the excessive frequency of diarrheal discharges depends on extra-infectious causes. Just to give an example, a chronic diarrhea with traces of blood that occurs immediately after a trip to African countries may be due more to ulcerative colitis than to an intestinal amoebae infection (as one might initially suppose).

Going back to the triggering cause is the first and most important step to establish a proper cure. For this purpose, the physical examination is indispensable to provide further clues about the nature of chronic diarrhea.

The most frequently performed assessment tests are:

  • Anoscopy: diagnostic test useful for detecting possible fistulas, ulcerations or fecaloma
  • Abdominal physical examination for the detection of inflammation, tumors, possible internal scars
  • Rectal exploration
  • Search for occult blood in stool
  • Further laboratory tests: complete blood count, albumin, liver function test, plasma electrolyte levels, thyroid-stimulating hormone levels, egg or pest finding in feces
  • Colonoscopy and sigmoidoscopy
  • Colon biopsy (indicated when microscopic colitis is suspected)


The treatment of chronic diarrhea aims to:

  • Eliminate the root cause
  • Balance bowel movements
  • Prevent any complications
  • Avoid relapses

The ideal cure for chronic diarrhea is clearly the elimination of the cause that caused it. However, as we have seen, the possible triggering factors are extremely numerous and heterogeneous; therefore, undertaking a specific cure immediately turns out to be rather difficult precisely because the cause is not always easily identifiable. For this reason, before starting any treatment for chronic diarrhea, the doctor should first determine the type (chronic watery, fat or inflammatory diarrhea). The next step involves the performance of specific laboratory tests for the differential diagnosis, therefore the implementation of an adequate cure.

When chronic diarrhea occurs with aggressive symptoms, such as to suggest a potentially serious pathology for the health and life of the patient (eg serious infections), prophylactic antibiotic therapy could constitute a valid and preliminary treatment option.

When the cause of chronic diarrhea is known, treatment is more immediate and simple:


If chronic diarrhea depends on a bacterial infection, antibiotics are the cure of choice. The duration of antibiotic therapy depends on the type of infection and the patient's state of health: in patients also suffering from Crohn's disease or ulcerative colitis, therapy must instead be followed for a longer period.


When chronic diarrhea depends on food intolerance, the most effective therapy is simply to remove that food from the diet.


If the cause of chronic diarrhea lies in the abuse of drugs or laxatives it is clear that the suspension of these medications can restore the disorder.

  1. SYMPTOMATOLOGICAL TREATMENT (no action on the cause)

The administration of some antidiarrheal drugs may be useful to temporarily relief the patient suffering from chronic diarrhea: "temporary" relief has been mentioned because these drugs do not act in any way on the triggering cause, but can postpone the stimulus to defecation. Among the drugs for the treatment of diarrhea we mention: Scopolamine, Atropine sulfate and intestinal motility inhibitors (eg Bismuth salicylate, Lactobacillus Acidophilus, Loperamide and Difenoxilate). Even soluble fiber supplements can help in the context of chronic diarrhea to regulate intestinal functions and promote the establishment of a symbiotic microbial flora.


When chronic diarrhea is closely linked to irritable bowel syndrome, the doctor prescribes to the patient drugs capable of reducing gastric secretion and intestinal motility (eg Atropine sulfate, Scopolamine). Prokinetic substances (eg psyllium) are also sometimes recommended to balance the frequency of evacuation, especially when episodes of chronic diarrhea and constipation alternate: in this specific case, psyllium exerts its action by absorbing excess fluids and increasing consistency of the kilo (fecal bolus).


As we have seen, chronic diarrhea may depend on a marked change in mood. In these cases, and subject to medical prescription, the patient can take serotonergic drugs, such as Venlafaxine and Alosetron. Even natural remedies for anxiety and stress can benefit the patient with chronic diarrhea.


Chronic diarrhea dependent on Crohn's disease is not as simple to treat, given the severity of the underlying disease. However, to alleviate the symptoms of chronic diarrhea in the context of Crohn's disease, the patient will need to pay close attention to the diet and take specific drugs (for further information, read drugs against Crohn's disease).

Chronic Diarrhea: What to do

In addition to the possible administration of specific drugs, chronic diarrhea must also be treated with the correction of certain behavioral and dietary habits.

For example, avoiding dehydration through fluid administration is a very important rule in the context of chronic diarrhea. We remember, in fact, that a state of severe dehydration can seriously compromise the vital functions of the subject.

Strictly avoiding alcohol and limiting beverages containing caffeine (tea and coffee) are two important rules for accelerating chronic post-diarrhea healing: in addition to favoring dehydration of the body, in fact, these substances tend to irritate the mucous membranes of the digestive system.

Special attention should also be paid to sweeteners: substances such as sorbitol, mannitol and xylitol (polyhydric alcohols) can in fact aggravate the condition due to their markedly laxative effect.

To alleviate the sensation of abdominal bloating that accompanies chronic diarrhea, it is advisable to avoid or limit as much as possible the intake of foods able to increase intestinal gases (eg beans, onions, peas and legumes in general).

Instead, a "categorical NO" is due to milk: diarrhea in general, worse than the chronic variant, drastically reduces the enzymatic proportion that populates the intestine, including lactase (an enzyme used to digest milk). By preventing the lactase from carrying out its activity, the digestion and absorption of lactose in various foods are compromised; therefore, a water booster is promoted (due to osmotic effect) and diarrhea is worsened by symptoms such as meteorism, nausea and flatulence.

Instead, all foods able to counter chronic diarrhea should be preferred, ie rice (with known astringent properties), apple and carrot (able to solidify feces), blueberry (anti-diarrheal properties) and potatoes.

A note of merit is therefore up to a healthy, balanced and regular diet, important for promoting recovery after several weeks of chronic diarrhea.