Diarrhoea and vomiting

Diarrhoea means passing loose or watery stools more often than normal for you. Vomiting is the forceful emptying of the stomach through the mouth. They may happen together or separately.

A short-lived infection of the stomach and bowel, called gastroenteritis, is a common cause. Contaminated food, medicines and other conditions can cause similar symptoms.

The main short-term concern is dehydration, when your body loses more water and salts than you can replace. Babies, older adults and people with long-term health conditions may become dehydrated more quickly.

Diarrhoea may be watery, urgent and difficult to control. You may also have stomach cramps, bloating, nausea, fever, headache or aching muscles.

Before vomiting, you may feel sick, sweaty or have extra saliva. Repeated vomiting can cause soreness, tiredness, thirst and light-headedness.

Signs of dehydration include:

• A dry mouth or strong thirst
• Dark urine or passing much less urine
• Dizziness, particularly when standing
• Unusual sleepiness, weakness or confusion
• Few or no tears in a crying child
• Fewer wet nappies than usual

Blood in diarrhoea may look red or make the stool black and sticky. Vomited blood can be red or resemble coffee grounds. These appearances need prompt medical assessment.

Common causes include viral gastroenteritis and food poisoning from germs or toxins in contaminated food. Other people who ate the same food may also become ill.

Medicines such as some antibiotics like amoxicillin or doxycycline, laxatives, diabetes medicines and cancer treatments can cause diarrhoea, nausea or vomiting. Do not stop prescribed medicine without advice. Contact a pharmacist or prescriber if symptoms began after starting it.

Alcohol, anxiety, overeating and sudden dietary changes can upset the stomach. Pregnancy commonly causes nausea and vomiting, although diarrhoea is not a usual feature of pregnancy itself.

Less common causes include food intolerances, coeliac disease, inflammatory bowel disease and irritable bowel syndrome. These are more likely when diarrhoea recurs or occurs with weight loss or ongoing pain. Migraine can also cause vomiting, particularly in children.

Urgent causes include appendicitis, a blocked bowel, pancreatic inflammation, severe infections and poisoning. Warning signs can include severe or localised pain, a swollen abdomen, green vomit, collapse or marked confusion.

Go to an emergency department or call your local emergency number if someone has:

• Vomit containing blood or material like coffee grounds
• Sudden, severe abdominal pain or a hard, swollen abdomen
• Green vomit with severe pain or inability to pass stool or wind
• Fainting, severe confusion, difficulty waking or breathing problems
• Suspected poisoning or swallowing of a harmful substance

Seek same-day medical advice if you cannot keep fluids down or have significant dehydration. Also get prompt advice for bloody diarrhoea, high fever with marked illness, worsening pain, or vomiting with a severe headache and stiff neck.

Babies, frail older adults, pregnant people and those with weakened immune systems may need assessment sooner. Seek advice about reduced feeding or wet nappies in a baby.

Book a routine appointment if vomiting lasts longer than two days, diarrhoea lasts longer than seven days, or symptoms keep returning. Ongoing weight loss, night-time diarrhoea or a lasting change in bowel habits also needs review.

Many brief episodes do not require tests. A healthcare professional may ask about timing, frequency, blood, fever, pain, medicines, pregnancy, recent travel, antibiotic use, unusual food and contact with unwell people.

An examination may check your temperature, pulse, abdomen and hydration. A stool sample may be needed if diarrhoea is bloody, prolonged, linked to travel or antibiotics, or part of a possible outbreak.

Blood tests can assess dehydration, kidney function, inflammation and body salts. Other tests may include a pregnancy test or abdominal imaging.

Replacing lost fluid is the priority. Take small, frequent sips if a full glass makes you vomit. Water is useful, while oral rehydration solution also replaces salts and sugar. Mix it exactly as directed on the packet.

Continue breastfeeding or usual milk feeds for a baby unless advised otherwise. Eat small amounts of ordinary food when able; there is usually no need to fast. Rich, fatty or spicy meals may be harder to tolerate.

Fruit juice and fizzy drinks can worsen diarrhoea, particularly in children. Avoid alcohol until recovered.

Ask a pharmacist before using anti-diarrhoeal medicine. It is not suitable for everyone and should not be used for bloody diarrhoea without medical advice. A clinician may prescribe anti-sickness medicine for severe or persistent vomiting.

Wash your hands with soap and water after using the toilet and before handling food. Do not prepare food for others while unwell. Stay away from work, school or nursery until at least 48 hours after the last episode of diarrhoea or vomiting.

Vomiting from a common stomach infection often settles within one or two days. Diarrhoea may continue for several days.

Appetite and energy may return gradually. Keep drinking regularly after vomiting stops. Seek advice if you improve and then worsen, or if diarrhoea continues beyond a week.

Most people recover without lasting problems. Dehydration is the main complication, especially when fluids cannot be kept down.

Is diarrhoea and vomiting contagious?

It can be. Infections spread through contaminated hands, surfaces, food or water. Wash with soap and water because alcohol hand gel does not reliably remove every stomach virus.

Should I eat while I am being sick?

Fluids are the priority. Eat small portions when able. You do not need a special restrictive diet.

Why did several people become ill together?

A shared meal, contaminated water or contagious infection may be responsible. If illness follows food from a restaurant or event, contact your local public health or food safety service.

Can I take my usual medicines?

Vomiting and dehydration can affect how medicines work or are absorbed. Ask a pharmacist or prescriber if you cannot keep medicine down, have missed doses or take medicines affected by dehydration.