This is having frequent loose watery stools. It occurs when the fluid cannot be absorbed from the contents of an individuals bowel or when extra fluid is secreted into the bowel causing watery stool. Usually it could be a symptom of bowel infection called Gastroenteritis which can be caused by some harmful micro organisms that may result from food poisoning I.e drinking contaminated water or eating contaminated food. It could be Acute or Chronic Diarrhoea.
Acute Diarrhoea :- this occurs suddenly and usually last a few days to weeks but resolves on its own.
Chronic Diarrhoea :- onset is not sudden and it usually lasts well over two weeks, this needs urgent medical attention to find the underlying cause and initiate treatment with the dreaded complication of both being Dehydration of varying degrees. Prevention and treatment should commence fast especially in children to avoid fatalities.
So, make sure you see your doctor asap