Chipotle is getting absolutely hammered right now, both in terms of its public image and its stock, and the company thank an ugly outbreak of norovirus in Boston for that — a very unpleasant disease that you definitely don’t want to catch.

The E. coli outbreaks in nine states were bad enough, but the report of a norovirus outbreak tied to a Boston area Chipotle restaurant really has the company reeling and health officials scrambling to contain, as we reported recently. But what exactly is the norovirus? Chances are, you’re not sure what it is, or if it’s something that you’re likely to get. But it’s something you definitely want to avoid at all costs, and it’s a lot more common that you think.

The folks across the pond have another name for norovirus: they call it the winter vomiting bug. We might call it the stomach flu, although it’s not related to influenza. Whatever you call it, it’s the most common cause of viral gastroenteritis. Gastroenteritis is a medical condition that results from inflammation of the gastrointestinal tract that involves the stomach and small intestine, and is accompanied by some pretty unpleasant symptoms: diarrhea, vomiting, abdominal pain, cramping — the works. Sometimes, it gets so bad it results in dehydration.

If you get it, drink lots of fluids. In severe cases, you might have to go to the hospital to get intravenous fluids.

And norovirus is a killer. There are about three to five billion cases each year, and it kills 1.4 million people annually.

Ever hear of those outbreaks of disease on cruise ships? That’s usually norovirus, which can sweep through hundreds of cruise ship passengers right away.

But it’s also a problem on dry land, with about half of all food-borne disease outbreaks blamed on it.

So no matter where you choose to eat, be careful. Norovirus is sure to give you a bad time if you eat the wrong thing.