My doctor said I had acute gastroenteritis. What does this mean?

Acute Gastroenteriti. Irritation & inflammation of stomach & intestines, most commonly caused by viruses, also called Stomach Flu, and presents with diarrhea, nausea, vomiting & abdominal cramps.
Acute stomach illnes. This is a generic term often used to describe acute episodes of nausea, vomiting and diarrhea. These symptoms are often caused by viral or bacterial infections and resolve on their own.