Diarrhea is usually a sign of some type of intestinal inflammation. Intestinal inflammation is usually caused by infection (bacterial or viral and rarely by a parasite or yeast). Much rarer causes for intestinal inflammation are ulcerative colitis and Crohn’s disease. Those 2 severe intestinal inflammatory diseases have unknown causes, but are probably autoimmune conditions.

Besides inflammation, diarrhea can be due to disturbed intestinal absorption, or "malabsorption". Malabsorption syndrome can be due to many causes. During this condition, food is not absorbed completely (especially fats) and are expelled outside of the intestines causing diarrhea.

One final possibility for diarrhea is irritable bowel syndrome (IBS). IBS is a functional intestinal disorder with no organic lesions. Constipation and diarrhea are the most common symptoms of IBS. Specialists believe that IBS is probably due to anxiety.

An intestinal infection can be proven with microbiological examination of the stool. Ulcerative colitis and Crohn’s disease can be diagnosed with a colonoscopy. Malabsorption syndrome includes a complicated diagnostic procedure depending on the cause. IBS is diagnosed when all organic reasons for diarrhea will be excluded.

You can visit your GP to investigate the cause of the symptoms, to search for the right diagnosis and start proper treatment.