Short answer: most food poisoning symptoms start within hours after eating contaminated food, but it can range from as soon as 30 minutes to several days depending on the cause. Details to help you understand timelines and what to expect:

• Common bacteria and toxins often cause symptoms within a few hours to a day. For example, Staphylococcus aureus toxin–related poisoning can appear as quickly as 30 minutes to several hours after ingestion, while other causes may take longer.

• Salmonella and many other bacteria typically present symptoms within about 6 hours to several days after exposure. The exact timing depends on the microbe and dose.

• Some infections (or toxins) can take longer, from 12 to 72 hours or more. In certain cases, symptoms may not begin until several days later.

• Symptoms commonly include nausea, vomiting, diarrhea, abdominal cramps, and sometimes fever. The duration of illness often ranges from under 24 hours to a couple of days, though more severe cases can last longer, especially in young children, older adults, or people with weakened immune systems.

Tips if you’re experiencing symptoms:

• If symptoms are severe, include high fever (over 102°F/38.9°C), blood in stool, dehydration, or you’re unable to keep fluids down, seek medical care promptly.

• Ensure you stay hydrated with small sips of clear fluids; avoid dairy if it worsens symptoms. Rest as needed.

• Food poisoning generally resolves on its own, but seek medical advice if you’re in a high-risk group (young children, elderly, pregnant people, or those with chronic illnesses).

If you’d like, specify your age, any immune concerns, and which symptoms you’re experiencing, and it can help tailor the guidance.