Escherichia coli is a Gram-negative cane (bacillus) of the Enterobacteriaceae family. Most E. coli are normal diners found in the digestive tract. The pathogenic strains of this organism are distinguished from normal flora by possessing virulence factors, such as exotoxins. Enterotoxigenic Escherichia coli (ECEP). It constitutes one of the main causes of infantile diarrhea, mainly in the underdeveloped countries, it is the quota of the well-known “traveler’s diarrhea”. What differentiates this type of bacteria is the expression of one or more enterotoxins and the presence of fimbriae used to adhere to the host’s intestinal cells. They are also characterized by the production of enterotoxins: thermolabile (LT) and thermostable (ST). These toxins increase the content of the mucosal cells which generates diarrhea, nausea and vomiting, with or without fever.