Most food poisoning is grim for a couple of days and then it's gone. You feel rotten, you stay near a toilet, you drink flat lemonade and feel sorry for yourself, and by the weekend you're more or less yourself again. That's the usual story for a healthy adult, and it's worth holding onto, because the panic ("was it the chicken? do I need a doctor?") often does more harm than the bug itself.
This is a plain-English guide to what's happening, roughly when, and what's actually useful to do. It's general information, not a diagnosis, and it doesn't replace the NHS. If something here doesn't match how you or someone you're looking after feels, trust that and get proper advice.
What food poisoning actually is
You get food poisoning from eating food contaminated with harmful germs, or with the toxins those germs leave behind. That second part matters and trips people up. Sometimes the bacteria are long dead by the time you eat the food, but the toxin they produced is still there, heat-stable, perfectly capable of making you ill. Reheating a dodgy rice dish until it's piping hot can kill the bug and still leave the toxin that ruins your evening.
The usual symptoms:
- Feeling sick (nausea)
- Being sick (vomiting)
- Diarrhoea, often watery
- Stomach cramps or a gripey, low tummy ache
- A high temperature, or feeling hot and shivery
- Aching, exhausted, generally off-colour
Nobody gets the full set. Some people just vomit once or twice and feel queasy. Others skip the vomiting entirely and it's all diarrhoea and cramps. A fair number simply feel wiped out and a bit feverish, like a short bout of flu that's settled in the gut. The intensity tells you more than the exact mix of symptoms.
When symptoms turn up
This is the bit that confuses everyone, because the gap between eating the food and feeling ill ranges from a couple of hours to several days, depending entirely on which bug you've picked up. A rough guide to common UK culprits:
- Norovirus comes on fast and hits hard. Often within a day or so, sometimes sooner, with sudden vomiting and diarrhoea that seems to arrive out of nowhere. It's the classic "winter vomiting bug" and it's wildly contagious.
- Campylobacter is the most common cause of bacterial food poisoning in the UK, usually from undercooked chicken or cross-contamination in the kitchen. It takes its time, typically two to five days, then brings cramps, fever and diarrhoea that can be properly painful.
- Salmonella also has a delay of roughly half a day to a couple of days, with diarrhoea, cramps and fever.
- E. coli can take a few days and sometimes causes a nastier, occasionally bloody upset.
- A toxin from food left too long in the danger zone (between fridge-cold and piping-hot) can hit within one to six hours. Cooked rice left out overnight is the textbook example.
Here's the practical consequence. Because the delay is often long, the meal that got you is frequently not the last thing you ate. People instinctively blame their most recent takeaway, but if you've got campylobacter, the culprit was more likely the meal from two or three days back. That's exactly why it's so hard to pin food poisoning on one restaurant with any confidence, and why a single sufferer rarely makes a watertight case on their own.
How long you'll feel awful
For most people the worst is over in a day or two, and the whole thing clears within about a week with no specific treatment. Antibiotics usually aren't needed and often aren't wanted, because they can prolong some infections rather than shorten them. Your body deals with it.
The real danger in those few days isn't the bug. It's dehydration. You're losing fluid and salts faster than you're replacing them, every time you're sick or run to the loo. That's what tips a miserable-but-fine situation into something that needs a doctor, and it's the thing to stay ahead of.
Looking after yourself at home
If you're an otherwise healthy adult with mild to moderate symptoms, home is the right place to be. Honestly, dragging yourself to a GP surgery or A&E with ordinary food poisoning mostly just spreads it around the waiting room. The NHS advice boils down to rest and fluids.
- Rest, and stay off work or school until you've gone 48 hours with no vomiting and no diarrhoea. Not 48 hours from when you first felt rough — 48 hours from the last episode.
- Drink plenty of fluids in small, frequent sips. Water's fine. A few small sips every few minutes stays down far better than gulping a pint and bringing it straight back up.
- Eat when you feel up to it. Don't force a roast dinner. Start small and plain: toast, a banana, a bit of rice, plain crackers. If the thought of food turns your stomach, leave it; fluids matter more than food in the short term.
- For the very young, the elderly, or anyone already unwell, ask a pharmacist about oral rehydration sachets. These replace the salts and water you're losing, which plain water alone doesn't fully do. You dissolve a sachet in water and sip it through the day.
A note on the medicine cabinet. Anti-diarrhoea tablets like loperamide can take the edge off if you absolutely have to get through a journey, but they're not a fix and you shouldn't take them if there's blood in your diarrhoea or a high fever, because in those cases keeping the bug moving through is the point. Paracetamol can help with aches and a temperature. Sugary fizzy drinks and fruit juice are best watered down rather than drunk neat — too much sugar can make diarrhoea worse.
And wash your hands properly. Soap and warm water, after the loo and before you touch any food, because norovirus in particular spreads with frightening ease. Alcohol gel doesn't reliably kill norovirus, so it's the sink, not the bottle. Don't cook for anyone else while you're ill or for 48 hours after you've stopped. If you've shared a bathroom, give the toilet, flush handle and taps a proper clean with a bleach-based product. A surprising number of household outbreaks are one person being ill and then innocently buttering everyone's toast.
A realistic scenario or two
Say you had a chicken wrap from a café on Monday lunchtime. Wednesday evening the cramps and diarrhoea start. You feel hard done by and you're sure it was the wrap. Maybe — but the two-to-three-day gap fits campylobacter, and that could just as easily have come from a barbecue, a different meal, or chopping raw chicken at home on Tuesday. The timing genuinely matters when you're trying to work out the source.
Or: a family meal, leftover rice that sat on the side for hours, reheated the next day. Within a couple of hours half the table is being sick. That fast, that synchronised, after a known dodgy dish — that's a far stronger pattern, and the kind of thing worth reporting.
When to stop self-treating and get advice
Most cases never need a professional. But some do, and knowing the line saves a lot of needless worry in both directions. Contact NHS 111 or your GP, or check the NHS website, if you or someone you're caring for:
- Has blood in their vomit or diarrhoea
- Has a very high temperature, or feels hot and shivery
- Shows signs of dehydration — very thirsty, peeing little or dark urine, dizziness, sunken eyes, persistent tiredness, a dry mouth
- Keeps being sick and can't keep any fluid down at all
- Isn't improving after a few days, or is getting worse
- Has severe stomach pain
Some people should get advice sooner rather than waiting it out: babies and young children, older people, anyone pregnant, and anyone with a weakened immune system or a serious long-term condition. For a baby or small child, the warning signs come faster and matter more. Fewer wet nappies, no tears when crying, unusual drowsiness or floppiness, or a child who's much harder to rouse than normal — don't sit on that, get help promptly. Dehydration in a little one moves quickly.
If anyone is seriously unwell — struggling to stay awake, very confused, signs of severe dehydration that aren't improving — call 999 or go to A&E. That's the small minority, but it's the one worth being clear about.
Reporting a suspected case
If you genuinely think a specific business made you ill, you can report it to the environmental health team at the relevant local council. Not the police, not the FSA directly — your local authority. They're the ones who investigate complaints, who can inspect the premises, and who can join the dots between several reports to spot a problem you'd never see from inside a single illness.
That last point is the real value of reporting. One person being sick proves very little. But if the council's already had three other reports naming the same place that week, your report becomes part of a pattern, and that pattern can stop other people getting ill. Note down what you ate, where, when, and when your symptoms started — that timeline is exactly what investigators work from.
We walk through the steps, what to include, and what realistically happens next in our guide on how to report a food business. If NHS 111 or your GP ask you to, do let them know too, because some infections like E. coli and salmonella are notifiable and get passed to public health teams whose whole job is catching outbreaks early.
What a hygiene rating tells you, and what it doesn't
A food hygiene rating is a snapshot from a business's last inspection by a council officer. It says how well the kitchen met hygiene standards on that particular day. It isn't a score for how the food tastes, and it isn't a live readout of whether the place is clean this very minute. Ratings change at the next inspection — a 2 can climb to a 5 once problems are fixed, and a 5 can slip if standards drop. You can read how the 0-to-5 scale actually works on our ratings explained page, and there's more on the mechanics in how food hygiene inspections work.
Use the rating for what it's good at. Checking a place before you order — look up any business and see both its score and the date it was last inspected — is a sensible habit, and a date from five years ago tells its own story. What a rating can't do is prove that one specific meal made you ill. A low score isn't evidence against a particular plate of food, and a top score is no cast-iron guarantee, because food poisoning can creep in from how something was stored, chilled or handled at any point, including after a glowing inspection. Treat the rating as one solid piece of the picture, sat alongside your own eyes, your common sense, and — if you do go down with it — the NHS advice above.