Diarrhoea and vomiting
Diarrhoea and vomiting almost always start suddenly and almost always settle on their own.
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Medicines commonly prescribed for Diarrhoea and vomiting
For informational purposes only. Always consult a doctor before taking any medication.
Dosage form: INJECTABLE, 2 mg/mLActive substance: ondansetronManufacturer: Accord Healthcare S.L.U.Prescription requiredDosage form: TABLET, 4 mgActive substance: ondansetronManufacturer: Neuraxpharm Spain S.L.Prescription requiredDosage form: CAPSULE, 2 mgActive substance: loperamideManufacturer: Teva Pharma S.L.U.Prescription not required
Diarrhoea and vomiting almost always start suddenly and almost always settle on their own. Behind them there is usually a gut infection, viral or food-related, and within a few days nothing is left of it. The danger in those days comes not from the symptoms themselves but from how much water and salt the body loses along the way. So at home there is really only one job: keep fluids going in. The second job is to notice in time that this particular case is not the ordinary kind. Blood in the stool, a high temperature, severe pain in the abdomen that will not ease, a recent course of antibiotics or a return from a trip change the picture entirely, and in those situations waiting is not an option.
The danger is not the diarrhoea, it is the fluid loss
An adult with healthy kidneys gets through a day or two of diarrhoea without harm as long as they drink. Small children and older people lose fluid faster and replace it worse: a child holds more water per kilo of body weight and loses more of it, while an older person often simply does not feel thirsty and is taking diuretics on top of that.
In an adult, dehydration shows up like this:
- a dry mouth, a sticky tongue, cracked lips;
- little urine, dark and strong-smelling, with many hours between visits to the toilet;
- thirst, weakness, vision dimming and dizziness on standing up;
- sunken eyes, a fast pulse, listlessness.
In a child you look at behaviour and nappies rather than at complaints. The warning signs are: a nappy that stays dry for many hours in a row, crying with no tears, dry lips and tongue, unusual sleepiness or, the other way round, inconsolable crying, and in a baby a sunken soft spot on the head. A child who has stopped drinking and refuses the breast or bottle needs to be seen by a doctor the same day, not left to see how the morning goes.
In an older person dehydration often looks like confusion: they muddle their words, become drowsy, walk unsteadily, fall. The family puts it down to age, when in fact the cause can be fixed within a day. Special care is needed for anyone taking diuretics, blood pressure medicines or certain diabetes drugs: with diarrhoea these push the blood pressure down further and strain the kidneys, so ask a doctor whether to keep taking them during these days.
How to give fluids so they stay down
The commonest mistake is trying to drink a whole glass at once. An irritated stomach sends a large volume straight back, the person concludes that water "will not stay down" and stops drinking altogether. The opposite works: one or two sips every few minutes, without a break, for many hours. A small child is given fluid from a teaspoon or from a needleless syringe into the cheek — tiny amounts, but constantly. That rhythm holds even with vomiting, because between one episode and the next some of the fluid does get absorbed.
The best option is a sachet of oral rehydration salts from the pharmacy. The ratio of salt to sugar in it is worked out so that water is absorbed faster than from plain drinking. Mix it exactly as the instructions say and with exactly the volume of water stated: a stronger solution makes the diarrhoea worse rather than helping.
What not to give:
- fizzy drinks and fruit juice — too much sugar, which pulls water into the gut and makes the diarrhoea heavier;
- sports drinks instead of rehydration solution: their make-up is different and not designed for this;
- baby formula watered down — formula is made up at its usual strength and water is offered separately, between feeds;
- alcohol and strong coffee.
Breastfeeding is not interrupted; if anything, offer the breast more often and for shorter spells. A formula-fed baby carries on with the usual formula, with small amounts of water or rehydration solution between feeds.
Eating in the first few days
Going without food is unnecessary and even counterproductive: the gut recovers faster when it is fed. Eat to appetite, in small portions, and whatever is tolerated. Rice, potato, pasta, banana, toast, soup and boiled meat usually go down easily. Fatty, fried, very spicy and very sweet food is harder work.
Milk deserves a separate word. After a gut infection the ability to digest milk sugar does not come back at once, so whole milk can add bloating and loose stools for a couple of weeks. This is temporary and does not mean an intolerance has developed; fermented dairy is usually tolerated better. Babies stay on their usual formula — lactose-free formulas are rarely needed and are a doctor's decision. Go back to normal food as soon as the stools start to thicken; long, strict diets speed nothing up.
When this stops being an ordinary tummy bug
A gut infection gives watery stools without blood, a moderate temperature and bearable cramps, and eases within a few days. Anything that does not fit that picture needs a doctor, and the same day rather than next week.
- Blood or mucus in the stool, or black tarry stools. That is no longer an ordinary virus: bacterial infections, inflammatory bowel disease, bowel ischaemia and bleeding higher up the digestive tract all behave this way.
- A high temperature with shivering, especially together with blood in the stool.
- Severe or worsening abdominal pain, pain that settles in one spot, a belly that is hard and tender to touch. Vomiting with pain like that is not coming from a gut infection but from appendicitis, an obstruction, or inflammation of the gallbladder or pancreas.
- A recent course of antibiotics. For weeks, and even a couple of months, afterwards diarrhoea can be caused by the bacterium Clostridioides difficile, which multiplies once the antibiotic has wiped out the normal gut flora. That diarrhoea is copious and foul-smelling, often with fever and pain, and it is treated with specific antibiotics. Medicines that slow the bowel are dangerous here.
- Coming back from a trip, particularly to hot countries: diarrhoea that drags on after travel often turns out to be parasitic, and a fever after the tropics means malaria and typhoid must be ruled out whatever the bowel is doing.
- Diarrhoea lasting more than a week, vomiting more than two days, diarrhoea that wakes you at night, noticeable weight loss.
- A weakened immune system, chemotherapy, pregnancy, serious long-term illness, recent abdominal surgery.
One more thing: vomiting without diarrhoea is often not about the gut at all. In children and older people it is how a urine infection shows itself; in people with diabetes, a sharp rise in blood sugar; in others, migraine or raised pressure inside the skull; and in older people, occasionally a heart attack that comes without the familiar chest pain.
Signs that mean calling an ambulance
The single emergency number across Europe is 112. Call if any of the following appears:
- vomiting blood or something that looks like coffee grounds; heavy bright red bleeding from the back passage; black tarry stools;
- green vomit in a child, or vomit that looks like bowel contents at any age;
- severe dehydration: the person is barely passing urine, cannot be persuaded to drink, is sluggish or losing consciousness, with cold pale skin and a racing pulse;
- sudden constant abdominal pain with a belly that has gone board-hard;
- fever together with a stiff neck, discomfort in bright light, a severe headache, or a rash that does not fade when pressed with the side of a glass;
- serious difficulty breathing, or blue or grey lips, skin or tongue;
- a child who is floppy, hard to wake, and not responding as usual;
- any suspicion that the person has swallowed a poison, mushrooms, a large dose of a medicine or a household cleaner.
In that state do not drive yourself and do not take the patient in yourself — call an ambulance. Have the list of their medicines ready.
Medicines: what helps and what harms
An ordinary gut infection needs no medicine at all; it needs water. But a few things are worth knowing in advance, because the mistakes here are always the same ones.
- Anti-diarrhoeal medicines (loperamide and the like) are acceptable only for adults, only with watery diarrhoea that has no blood and no fever, and only briefly — to get home, for instance. With blood in the stool, with a high temperature, and after a recent course of antibiotics they must not be taken: holding the contents in the bowel also holds in the bacteria and their toxins, and with some infections and with inflammatory bowel disease that ends in a serious complication. Children are not given them.
- Children and teenagers are not given aspirin during a feverish illness, in any form. For fever and pain, paracetamol is used at the dose by weight or age given on the leaflet.
- Anti-inflammatory painkillers such as ibuprofen are best avoided during these days: they irritate the stomach and, alongside dehydration, put extra strain on the kidneys.
- Anti-sickness medicines are prescribed by a doctor. One chosen without advice can mask surgical pain and cost time.
- Antibiotics do nothing for a viral gut infection, and sometimes do harm: they prolong shedding of the germ and cause diarrhoea in their own right. The decision to use one belongs to a doctor and usually follows a stool test.
- Adsorbents and probiotics are harmless, but their effect is modest and they are no substitute for drinking.
Something people rarely think about: with vomiting and diarrhoea, tablets may not be absorbed at all. That applies to the contraceptive pill, which needs backup protection during the illness and for a few days after, and to any medicine you take regularly. If you were sick soon after taking an important one, ask a doctor whether to repeat the dose.
How to avoid passing it on
Gut viruses spread extremely easily: a microscopic amount on a door handle or a towel is enough. So the precautions are worth taking, and the main one is simple.
- Wash your hands with soap under running water after the toilet and before eating. Alcohol hand gel works poorly here — against norovirus, the commonest culprit, it barely does anything, and soap and water are what is needed.
- Stay at home and keep away from school, nursery and work until two days have passed since the last episode of vomiting or diarrhoea.
- Do not prepare food for other people while you are ill.
- Do not share towels, crockery or cutlery; wash clothing and bedding soiled with stool or vomit separately on a hot wash.
- Wipe the toilet seat and flush handle, taps, door handles and light switches with detergent every day.
- Stay out of swimming pools for two days after everything has stopped.
Online consultation
Diarrhoea and vomiting are a subject where a remote appointment genuinely helps, because the decision is made by asking questions. The doctor will go through how many days it has lasted, what the stool looks like, whether there is fever or blood, what you ate, where you travelled and what medicines you have taken in recent weeks, and will tell you the thing that matters: whether you can stay at home or need to be seen today. They will also explain how to make up and how to give rehydration solution to a child, which of your regular medicines are worth discussing with your own doctor over these days, and can arrange a stool test if one is needed.
An online appointment does not replace an examination where the abdomen has to be felt, and it is no use in severe dehydration: if a person cannot be got to drink, fluid goes into a vein. For vomiting blood, black stools, sudden severe abdominal pain or deep drowsiness you need an ambulance, not a chat.
This material is for information only and does not replace medical advice.
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