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How Long Until Food Poisoning Takes Effect?

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How Long Until Food Poisoning Takes Effect?

Dec 26, 2022

Sometimes we eat something we wish we hadn't. Emergency room physician Troy Madsen, MD, says food poisoning generally takes about six hours to take effect, but most people get through it all right. Learn about the symptoms of food poisoning and things you can do to help yourself get through it.

Episode Transcript

Interviewer: Food poisoning. How long after you eat it will it take to affect you? You're at a barbecue or a party or something and you ate a little something and now you're kind of wondering, "Oh, man. Maybe that chip dip was out a little too long." You're worried that you're going to get food poisoning. How long is it going to take until you actually know whether or not you did?

Dr. Troy Madsen is an emergency room physician at University of Utah Health. Food poisoning. How long after you eat something will it take to affect you?

Dr. Madsen: So food poisoning's going to take about six hours to hit you. And when I tell you this, I'm speaking from personal experience because I had some really bad potato salad once, that I knew was bad, and I still ate it and six hours later, I was as sick as I've ever been.

Interviewer: And what are those symptoms?

Food Poisoning Symptoms

Dr. Madsen: So, typically, you're going to get some nausea, vomiting, maybe you get some diarrhea as well. Abdominal cramping, you might hurt all over, you might have a headache with it as well, but, typically, it's going to be those stomach, those GI symptoms. Just lots and lots of vomiting as your body is reacting to that bacteria that are in the food that made you sick.

Interviewer: So about six hours, normally. Does it vary from bacteria to bacteria?

Dr. Madsen: It does, but the most common one we see is Staph aureus, which affects thing like potato salad, mayonnaise-based sorts of foods. And that's usually what we're seeing, where you're at a barbecue, you're at a dinner, these things are left out too long, someone brought it from home and forgot it in their car and then goes out and gets it, you know. All these kinds of bad scenarios that are setting it up to really start to grow bacteria in there. And so, most of the time, it's six hours.

Interviewer: All right and how . . . does it automatically cause symptoms if you eat something that could be potentially bad, or do some people just react differently?

Dr. Madsen: I think some people it just depends, maybe . . . I don't know. You know, like I said, I had a personal experience with it and I knew this was not great potato salad, but I'm like, "I've got a strong stomach."

Interviewer: I guess you didn't, huh?

Dr. Madsen: I guess not. So I don't know if there's just, like, a certain threshold where if you eat X amount, you will get sick. If you eat less than that, you won't get sick. It's either really bad or it's not bad at all. Seems like most cases we see are people who come in who are feeling really sick from this.

Interviewer: Sure, which would make sense if they're coming into the emergency room, I suppose. So if some sort of food poisoning, or something I believe to be food poisoning, hits, you know, it's the six hours later after I ate something, maybe it was even at a restaurant, should I automatically be worried, or will my body kind of take care of it?

Food Poisoning Treatment

Dr. Madsen: Your body should take care of it. You know, if you've got other illnesses like kidney disease, heart problems, issues with dehydration, then I'd be more concerned because you're going to lose a lot of fluid. But if you're otherwise healthy and you think you can get through it, it's probably going to last six to 12 hours, and then you should feel better. You may want to go to the ER if you need to get some fluids, need to get some medication for nausea and vomiting, just to get through it. But the reality is most people are going to get through it okay. They're going to feel pretty crummy, but come out of it feeling weak, but feeling all right after 12 hours.

Interviewer: Would an urgent care be able to help you with those things, an IV and medication?

Dr. Madsen: They might be able to. The problem is if you go in an urgent care and you're just vomiting a lot, they might just get concerned enough, they might just send you straight to the ER. So it's kind of a tough call. Your doctor also might be able to call in a medication for you, some nausea medication, and maybe someone could pick it up for you. Because if you could just get that stuff in your system, you should be able to get through it okay.

Interviewer: Got you. And other than my own personal health, could it be something else that's more insidious than just food poisoning that would cause concern? I suppose if it doesn't stop in 12 hours, that's when . . .

Dr. Madsen: Yeah. It absolutely could, and that's the tough thing with food poisoning. We have people come in all the time that say, "I've got food poisoning," and honestly, I have no way to know unless they tell me, "Yeah, this other person was there and they got sick too and ate the same thing." Could be a virus, could be appendicitis, could be a bowel obstruction. There are lots of things that go through my mind so, definitely, if you're not feeling better after even six hours, you may consider getting checked out. And if you're having lots of abdominal pain, bloating in your abdomen, like your abdomen just feels like it's really distended, like it's sticking out, or you're really tender in the right, lower side of your abdomen, those are all things that might suggest something else going on.

updated: December 26, 2022
originally published: February 3, 2017