E. coli (Escherichia coli), is a type of bacteria that normally lives in your intestines. It’s also found in the gut of some animals. Most types of E. coli are harmless and even help keep your digestive tract healthy. But some strains can cause diarrhea if you eat contaminated food or drink fouled water. While many of us associate E. coli with food poisoning, you can also get pneumonia and urinary tract infections from different types of the bacteria. In fact, 75% to 95% of urinary tract infections are caused by E. coli.