Diarrhea for a Week – Causes and How Long Should It Last

Most of the time diarrhea is acute. This means that it arises suddenly, is often intense and resolves quickly within a few days. Sometimes no treatment is necessary for it to ease and eventually stop. However, when diarrhea continues for longer than a few days and persists up to a week or more then it becomes a cause for concern for most people. Diarrhea for a week or longer usually indicates a more serious cause and there is also a higher risk of complications like dehydration setting in.

How long should diarrhea last?

There is no definitive period for how long diarrhea should last. It is only a symptom of some underlying disorder, usually involving the bowels. Depending on the duration, it may be classified as acute, subacute or chronic.

  • Acute diarrhea lasts for up to 2 weeks.
  • Subacute diarrhea persists for 2 to 4 weeks.
  • Chronic diarrhea continues for more than 4 weeks.

While most of us expect sudden and severe diarrhea to ease and possibly fully resolve within a few days, it can persist for a week or more and still be considered acute. The duration that diarrhea lasts depends on a host of factors such as the cause of the diarrhea, the individual’s immune defenses and overall health status, dietary and lifestyle factors, medication and other treatments, the normal intestinal flora (normal “good” bacteria in the bowels) and rehydration.

Read more on uncontrollable diarrhea.

For example, a person with AIDS may experience chronic diarrhea due to their weakened immune system while a person who takes antibiotics for diarrhea may then experience secondary antibiotic-associated diarrhea. Even rehydrating incorrectly with beverages that contain too much or too little electrolytes may further aggravate existing diarrhea. Therefore the time for which diarrhea lasts may be variable.

Diarrhea that Lasts for a Week

Diarrhea that lasts for a few days can lead to serious complications even in such a short period of time. Death is even a possibility. However, most of the time diarrhea that lasts for a few days is not as serious. When the diarrhea persists, then the chances of complications increases. The main complication that is often the leading cause of death from diarrhea is dehydration.

In this case, the loss of water and electrolytes causes a host of disruptions throughout the body. Most significantly it can affect the heart, kidney and respiratory activity. Dehydration can be prevented and treated with adequate rehydration, be it oral or intravenous. However, sometimes rehydration therapy is not sufficient to prevent and treat dehydration thereby leading to serious complications and even death.

The longer diarrhea lasts the more likely that dehydration will be severe. Furthermore there are also disturbances to the normal intestinal flora which may not be able to recover spontaneously if the diarrhea has been too prolonged. This can then cause a continuation of diarrhea even though the initial cause has been treated, eradicated and resolved. Once again this may lead to dehydration.

Causes of Diarrhea for a Week

The causes of diarrhea that lasts for a week or more is largely the same as diarrhea that lasts for even a few days. Even with common causes of diarrhea, some people may only experience a problem for a few days while for others the diarrhea may persist for longer periods of time. Diarrhea should always be investigated by a medical professional to identify the exact cause so that the correct treatment can be prescribed.

Read more on causes of sudden diarrhea.


Infections are one of the most common causes of diarrhea. It affects every person at some point in their life, often occurring yearly particularly in children. In most of these cases the diarrhea is due to a viral infection. For example rotaviruses that causes outbreaks of viral gastroenteritis (“stomach flu”). Bacteria are another common infectious cause of diarrheal illnesses as is seen with food poisoning. Protozoa, like Giardia lamblia, may also cause diarrhea but viruses and bacteria are more common causes of infectious diarrhea.


In autoimmune diseases, the immune system attacks specific tissues and causes inflammation. With inflammatory bowel disease (IBD), there is inflammation of the bowels and sometimes of other parts of digestive tract. The exact cause of IBD is unclear. Celiac disease is a condition where the bowel becomes inflamed as a result of contact with gluten. It arises due to a combination of genetic and environmental factors. Diarrhea is one of the main symptoms in these autoimmune conditions of the bowels.

Foods and Drinks

Foods can also cause diarrhea for various reasons. Sometimes foods and beverages are contaminated with infectious agents like viruses or bacteria that can cause diarrhea, or contain toxins of these agents that may then lead to diarrhea. In other conditions, certain foods trigger bowel inflammation which can lead to diarrhea as in celiac disease.

Food intolerances are where the body cannot digest certain nutrients and these residual nutrients lead to bowel irritation resulting in symptoms like diarrhea. Lactose intolerance is an example. In malabsorption syndromes, the body is not able to absorb certain nutrients which can lead to bowel symptoms like diarrhea. Fructose malabsorption is one such case.

Medication and Surgery

Several drugs may cause diarrhea as a side effect. Laxatives can lead to diarrhea if used in excess and for prolonged periods for time. Antibiotics may cause a condition known as antibiotic-associated diarrhea. In these instances the diarrhea should resolve onc the causative drug is discontinued.

Diarrhea may also occur in certain situations following surgery. This is seen with abdominal surgery. In particular in may occur when there is a removal of a section of the digestive tract, as may be the case for cancer. It can also occur with gallbladder removal especially when fatty foods are consumed.


Functional bowel conditions occur for no clearly identifiable reason. These are conditions where there is an abnormality in the bowel physiology but it is not due to any disease. Irritable bowel syndrome (IBS) is one such type of functional bowel disoder. In IBS with diarrhea, the change in bowel habit causes frequent bowel movements and even diarrhea along with the characteristic abdominal pain and cramps.

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