Food Poisoning and Stomach Infections: Treating Them Safely at Home
Acute gastroenteritis is one of the most common illnesses and one of the most commonly mistreated. The treatment is mostly fluid, the antibiotics usually prescribed are usually unnecessary, and the anti-diarrhoeal tablets people reach for are sometimes dangerous.
Causes
Viral, the majority: norovirus, rotavirus in children, adenovirus. Typically vomiting prominent, watery diarrhoea, low fever, lasting one to three days.
Bacterial: Salmonella, Shigella, Campylobacter, E. coli, Vibrio, Staphylococcus aureus toxin. More likely to cause higher fever, blood or mucus in stool, and severe cramping.
Parasitic: Giardia causing prolonged bloating and foul greasy stools, Entamoeba histolytica causing dysentery.
Toxin-mediated food poisoning: symptoms within 1 to 6 hours of eating, mostly vomiting, from pre-formed toxin in food left out too long. Rice left at room temperature and reheated is the classic source.
Timing helps: very rapid onset after a meal suggests toxin; 12 to 72 hours suggests bacterial or viral infection.
The treatment is fluid
Oral rehydration solution is the single most important treatment, and the proportions matter. The glucose is not for energy; it is there because glucose and sodium are absorbed together through a co-transporter, which is what makes ORS work when plain water does not.
Use a standard ORS sachet in the exact volume of clean water stated on the packet. Do not use half a sachet in a glass, and do not add sugar, salt or lemon to it.
If no sachet is available, the WHO home formula is six level teaspoons of sugar and half a level teaspoon of salt in one litre of clean water. It should taste no saltier than tears. Too much salt is dangerous, particularly in small children.
Drink small amounts frequently — a few sips every five minutes — rather than large volumes, which provoke vomiting. After each loose stool, an adult should take roughly 200 to 400 ml; a child under two, about 50 to 100 ml.
Not substitutes for ORS: commercial sports drinks and packaged soft drinks, which have too much sugar and too little sodium and can worsen diarrhoea; plain water alone in heavy losses; and very sugary juices.
Other useful fluids alongside ORS: rice water or kanji, thin dal water, buttermilk, coconut water, and clear soups.
Unlock More Content
Watch a short ad to continue reading the rest of this article for free.
Preparing your free unlock…
Eating
Do not starve. Resume eating as soon as it is tolerated, which shortens the illness and preserves the gut lining. Start with bland, starchy, easily digested foods: khichdi, curd rice, bananas, toast, boiled potato, rice, idli. Avoid very fatty, very spicy and very sugary food, and avoid milk temporarily if it clearly worsens things, since transient lactose intolerance after gastroenteritis is common.
Zinc supplementation for 14 days reduces the duration and severity of diarrhoea in children and reduces recurrence over the following months. This is well established and still under-used.
Medication
Loperamide may be used by adults with watery diarrhoea and no fever or blood. Do not use it with fever, with blood or mucus in the stool, or in children, because slowing the bowel in invasive bacterial infection can cause serious complications.
Antiemetics such as ondansetron can help a child keep ORS down and are useful in that specific role.
Antibiotics are not needed for most cases and can prolong carriage, cause resistance and, in some E. coli infections, increase the risk of a serious kidney complication. They are reserved for dysentery with blood, suspected typhoid, cholera, confirmed parasitic infection, severe illness, and immunocompromised patients.
Probiotics may modestly shorten the illness; the evidence is reasonable for specific strains.
Signs of dehydration
Mild to moderate: thirst, dry mouth, reduced urine, darker urine, tiredness.
Severe, needing hospital:
- Very little or no urine for 8 hours or more
- Sunken eyes; in infants, a sunken fontanelle
- No tears when crying
- Skin that stays pinched when released
- Lethargy, floppiness, difficulty waking
- Rapid breathing or rapid weak pulse
- Dizziness or fainting on standing
- Confusion
- Cold, mottled hands and feet
Go to hospital when
- Signs of severe dehydration
- Unable to keep any fluid down for several hours
- Blood in the stool or vomit
- High fever, or fever lasting more than three days
- Severe or localised abdominal pain, particularly if it settles in one place
- Diarrhoea lasting more than a week
- Any infant under six months, or any child who looks seriously unwell
- Older adults, pregnant women, people with diabetes, kidney disease or immunosuppression
- Recent travel to an area with cholera or typhoid
- Recent antibiotic use, which raises the possibility of Clostridioides difficile
- Reduced consciousness or confusion
Preventing it
- Wash hands with soap before eating and after the toilet. Alcohol gel does not kill norovirus well; soap and water does
- Drink safe water: boiled, filtered or bottled from a reliable source
- Avoid ice, cut fruit, salads and juices from uncertain sources
- Eat food hot and freshly cooked; avoid food standing at room temperature
- Do not leave cooked rice out; refrigerate within an hour
- Keep raw and cooked food separate, and use separate boards
- Wash fruit and vegetables in safe water
- Avoid raw and undercooked meat, eggs and shellfish
- Rotavirus vaccination for infants, and typhoid and hepatitis A vaccines where appropriate
- An ill person should not cook for others, and should not return to food handling for 48 hours after symptoms stop
This is general information. Severe dehydration, bloody diarrhoea and illness in infants or older adults need medical care rather than home management.