Food Poisoning: When to Go to the ER (7 Warning Signs)

It started with a mild cramp after dinner, then came the long night: nausea, vomiting, repeated trips to the bathroom. Now it's 3 a.m. and you're wondering whether this is something that passes with sleep, or whether you should get dressed and go. The honest answer: most of the time, it passes. But there are specific signs that mean your body has fallen behind on what it can replace by itself, and knowing them is all that matters tonight.

7 food poisoning warning signs that mean go to the ER

• Signs of dehydration: very little or dark urine, dizziness on standing, a dry mouth, or a fast heartbeat.
• Being unable to keep any fluids down, even small sips.
• Blood in your vomit or stool, black stool, or vomit that looks like coffee grounds.
• A high fever.
• Severe or worsening abdominal pain.
• Diarrhoea lasting more than a few days, or vomiting for more than about two days.
• Call 911 for confusion, fainting, signs of shock, or blurred or double vision, drooping eyelids or difficulty swallowing (which can point to botulism).

In children, treat no wet nappy for several hours or crying without tears as dehydration that needs to be seen.

How long it lasts, and what usually causes it

Food poisoning comes from food or water contaminated with germs (bacteria, viruses or parasites) or the toxins they produce. Well-known causes include Salmonella, E. coli, norovirus and Campylobacter. When symptoms start depends on the germ: some cause vomiting within hours of eating, others take a day or several days to show — so the last meal isn't always the culprit. Most cases improve within one to three days, and the NHS says symptoms usually pass within a week.

Summer and late-summer heat in Amman makes both halves of the problem easier: food spoils faster out of the fridge, and your body is already losing more fluid through sweat, so it reaches dehydration sooner once vomiting and diarrhoea are added.

Food poisoning or a stomach bug?

The symptoms overlap heavily — nausea, vomiting, diarrhoea, cramps and sometimes fever — and often you can't tell the two apart from symptoms alone. Food poisoning is more likely if several people who ate the same food fell ill around the same time, while a stomach virus usually passes from person to person in a household over several days. In practice, the label matters less than you'd think: home care is the same, and so are the warning signs.

How to rehydrate properly

• Small, frequent sips rather than large amounts at once — an irritated stomach tolerates little and often much better.
• Oral rehydration solution from a pharmacy replaces lost salts and sugar, and is the best choice when fluid loss is heavy, or for children and older adults.
• Keep eating when you're able — small, plain meals. There's no need for a long fast.
• Avoid alcohol, and go easy on caffeinated or very sugary drinks.
• Be cautious with antidiarrhoeal medicines: avoid them if there's blood in your stool or you have a fever, and ask a pharmacist or doctor first. Never give children antidiarrhoeals meant for adults.

Dehydration signs in adults and children

In adults

• Very little urine, or dark, strong-smelling urine.
• Dizziness or light-headedness, especially when standing up.
• A dry mouth and lips, and strong thirst.
• A fast heartbeat, and unusual tiredness or weakness.

In babies and young children

• No wet nappy for several hours, or far fewer than usual.
• Crying without tears, and a dry mouth.
• Sunken eyes, or a sunken soft spot on a baby's head.
• Unusual drowsiness, floppiness or irritability.

Young children become dehydrated much faster than adults, so with a baby, don't wait for all of these to appear.

Who should be seen sooner

Some people are affected faster or more severely, and deserve an earlier assessment even if symptoms seem moderate:

• Babies and young children, and older adults.
• Pregnant women — some foodborne germs, such as listeria, can affect a pregnancy, so any food poisoning symptoms during pregnancy are worth a call to your doctor.
• People with weakened immunity (from illness, chemotherapy, or immune-suppressing medicines).
• People with kidney disease.
• People taking diuretics, diabetes medicines, or GLP-1 medicines such as Ozempic — dehydration can upset blood sugar control or strain the kidneys. See our guide on Ozempic warning signs that need the ER.

Urgent care or the ER?

For mild to moderate dehydration, symptoms that are dragging on longer than expected, or when you simply need someone to check, urgent care sees walk-ins around the clock, with an on-site laboratory, X-ray and ultrasound, and can assess and treat dehydration. Go straight to the emergency department — or call 911 — for:

• Confusion, fainting or extreme drowsiness, or cold, pale skin with a fast, weak pulse (signs of shock).
• Blurred or double vision, drooping eyelids, difficulty swallowing or speaking, or muscle weakness — neurological signs that can point to botulism.
• Vomiting blood or material that looks like coffee grounds, or bloody or black stool.
• Severe or worsening abdominal pain — especially pain that started around the navel and moved to the lower right, which can be appendicitis rather than food poisoning.
• Being completely unable to keep any fluids down, or passing no urine for many hours.

If your symptoms started as burning in your mouth or chest after a spicy meal rather than vomiting and diarrhoea, our guide on when a spicy food reaction is an emergency is closer to what you're looking for. And if you suspect a reaction to spicy food rather than poisoning, read can you be allergic to spicy food?.

Related guides: stomach pain: when to go to the ER and getting medical care in Amman as a tourist or expat.

Related guides: child vomiting and diarrhoea: dehydration signs.

Sources

• NHS — Food Poisoning
• NHS — Dehydration
• CDC — Symptoms of Food Poisoning
• World Health Organization — Food Safety