What should you know about organisms causing food poisoning?

Bacteria can multiply in food held or cooked unsafely, while viruses may spread when food or hands are contaminated. Parasites can be acquired from some food or water exposures. Some illnesses come from a toxin already present in food, so symptoms can begin even when the organism is no longer active. Food poisoning presents with digestive symptoms, but those symptoms also occur in other conditions. The pattern, suspected food, travel, other people who became ill, and severity help a clinician decide whether testing is useful.

Focus on fluid replacement. Take small, frequent sips of water or correctly prepared oral rehydration solution, especially if vomiting makes larger drinks difficult. Rest, wash hands thoroughly after using the toilet and before food preparation, and avoid preparing food for others while unwell. Keep a note of what was eaten, when symptoms began, and whether anyone else is ill. Do not use leftover antibiotics or anti-diarrhoea medicines without clinical advice, as they are not suitable for every cause.

Seek urgent care for blood in stool or vomit, severe or persistent abdominal pain, confusion, fainting, signs of dehydration, inability to keep fluids down, or a high fever with worsening illness. Prompt advice is also sensible for infants, older adults, pregnant people, people with weakened immunity, and anyone with significant kidney, bowel, or metabolic conditions. Intravenous fluid treatment may be needed when drinking cannot replace losses.

Ask whether stool testing is appropriate, how to prevent passing the illness to others, whether any medicine is advised, and which changes mean you should return for care. Mention recent travel, restaurant meals, undercooked foods, untreated water, and contact with animals or sick people.