Diarrhea, traveler's: Diarrhea illness associated with travel to a foreign country. Among the causes of traveler's diarrhea are viruses and enterotoxigenic E. coli (ETEC). E.coli is a particular type of bacteria that normally lives in the intestines of people (and animals). Most strains of E coli are quite harmless. They are simply part of the normal intestinal flora. However, there are some kinds of E. coli that are capable of causing disease. Not all E. coli bacteria that cause disease are alike. There are multiple classes of "bad" E.coli. The enterotoxigenic E.coli (ETEC) constitute a class of "bad" E.coli. They produce toxins (poisons). The ETEC toxins do not injure or kill the cells lining the intestines. They alter the metabolism of these cells, disturbing the regulation of fluid and electrolytes (like sodium and potassium) absorbed from the intestines. Instead of absorbing fluid, the intestinal cells permit fluid to be secreted into the intestine. This causes diarrhea. ETEC causes diarrhea in infants and traveler's diarrhea. ETEC is a cause of food poisoning. The cornerstone of ETEC therapy is replacement of fluids and electrolytes (sodium and other ions) lost in the diarrhea. The ideal approach to ETEC is to avoid exposure to it.