Online Doctor's Note for a Stomach Bug

How long a stomach bug usually lasts

Norovirus is the leading cause of vomiting and diarrhea in the United States, and it’s the illness most people mean by “stomach bug,” even though the CDC notes it isn’t related to influenza despite the nickname “stomach flu.” Symptoms typically start 12 to 48 hours after exposure, and most people feel better within 1 to 3 days. The catch is that you can keep spreading the virus for longer than you’re sick: the CDC recommends staying home until at least 48 hours (2 days) after symptoms stop, both to protect your own recovery and to avoid passing it to coworkers, classmates, or family.

Why staying home matters here specifically

A stomach bug spreads easily, through direct contact with someone who’s sick, contaminated food or surfaces, or unwashed hands. That’s part of why employers and schools tend to be more willing to excuse this kind of absence without much friction: it’s a genuinely contagious illness, not just a discomfort. Frequent handwashing, disinfecting shared surfaces, and washing laundry in hot water are the main things the CDC recommends to limit spread while you or a family member are contagious. Young children, older adults, and anyone with another underlying illness are more likely to develop severe symptoms or dehydration from a stomach bug, so it’s worth being more cautious about exposure and about watching for warning signs in those groups specifically.

When it’s more than a stomach bug

Most cases resolve with rest and fluids, but MedlinePlus lists specific warning signs that call for medical attention rather than just time at home: a change in mental state such as unusual irritability or low energy, diarrhea lasting more than 2 days, a high fever, frequent vomiting, six or more loose stools in a day, severe abdominal or rectal pain, or stools that are black, tarry, or contain blood or pus. Signs of dehydration, such as a dry mouth, dizziness when standing, or noticeably less urination, are also worth calling a provider about, especially for young children, older adults, or anyone with another health condition. None of these are things a same-day absence note is meant to address.

What to tell your employer or school

You don’t need to specify that the illness was a stomach bug for the note to be valid; it simply confirms you were reviewed, reported symptoms, and were advised to rest for the dates listed. If your workplace or school has a policy requiring documentation only after a certain number of sick days, or a specific format for excuse notes, check that ahead of time, since those requirements are set locally and this note documents the absence rather than overriding any particular policy.