What are the symptoms of E. coli infection?

Symptoms start about 7 days after you are infected with the bacteria.. The first sign is severe abdominal cramps that start suddenly. After a few hours, watery diarrhea starts. The diarrhea causes your body to lose fluids and electrolytes (dehydration). This makes you feel weak and tired. The watery diarrhea usually  lasts for about a day. Then the diarrhea changes to bright red bloody stools. The infection makes sores in your intestines, so the stools become bloody. Bloody diarrhea lasts for 2 to 5 days. You might have 10 or more bowel movements a day. Some people say their stools are "all blood and no stool."

In addition, you may have a mild fever or no fever at all. You may also develop nausea or vomiting. If you have any of these symptoms -- watery, bloody diarrhea, cramps, fever, nausea or vomiting -- it is important to seek medical attention as soon as possible.