Gastroenteritis

Gastroenteritis is inflammation of the stomach and intestines, most often caused by a virus (norovirus and rotavirus are common culprits), though bacteria and parasites can also be responsible.

Symptoms

Watery diarrhea, nausea, vomiting, abdominal cramps, and sometimes a low-grade fever are typical, usually starting within one to three days of exposure and lasting one to three days for viral cases, occasionally longer.

How It Spreads

Gastroenteritis spreads easily through contaminated food or water, contact with an infected person, or touching contaminated surfaces — outbreaks are common in settings like schools, daycares, and cruise ships because of how little exposure it takes.

Preventing Dehydration

Dehydration, not the infection itself, is the main risk — especially for young children, older adults, and anyone unable to keep fluids down. Small, frequent sips of water, oral rehydration solutions, or diluted juice are better tolerated than large amounts at once; signs of dehydration include reduced urination, dry mouth, dizziness, and unusual sleepiness.

Treatment

Most cases resolve on their own with rest and rehydration; antibiotics don't help viral gastroenteritis and are only used for confirmed bacterial cases. Current guidance favors resuming a normal, age-appropriate diet as soon as it's tolerated rather than restricting to bland foods — a full diet supports recovery better than a limited one like the old BRAT diet (bananas, rice, applesauce, toast), though bland foods are a fine option if that's what feels easiest at first.

When to See a Doctor

See a doctor for signs of dehydration, blood in vomit or stool, a fever above 39°C, symptoms lasting more than a few days, or an infant or young child who can't keep fluids down.