Vomiting: Causes and When to Worry

Vomiting vs regurgitation

Vomiting is an active process. You usually feel nauseous first, retch, then the abdominal muscles and diaphragm contract hard to push stomach contents up. Regurgitation is passive: food or acid comes back up into the mouth without nausea or effort, typically from reflux or swallowing problems. In babies, small effortless "spit-ups" after feeds are regurgitation and are usually normal.

Common causes of vomiting

Stomach bugs and food poisoning

• Viral gastroenteritis: norovirus in adults and rotavirus or norovirus in children. Sudden vomiting, then watery diarrhea, cramps and sometimes fever. Lasts 1 to 3 days. Often several people in a household or group are affected.
• Food poisoning: vomiting within 1 to 6 hours of eating suggests a toxin from bacteria such as Staphylococcus aureus or Bacillus cereus (often from rice). Salmonella and Campylobacter take 12 to 72 hours and cause more diarrhea and fever.

Other everyday causes

• Motion sickness: in cars, boats or planes.
• Alcohol: irritates the stomach and affects the brain's vomiting center.
• Medicines: antibiotics, opioids, chemotherapy, iron supplements, some diabetes medicines and many others.
• Severe pain or anxiety: can trigger vomiting by itself.
• Pregnancy: morning sickness is common in the first 12 to 14 weeks. Severe, persistent vomiting with weight loss is hyperemesis gravidarum.

Vomiting with headache

• Migraine: throbbing headache with nausea, vomiting and sensitivity to light and noise. In children, migraine can show up mainly as vomiting.
• Concussion: vomiting after a head injury needs urgent assessment.
• Meningitis: headache, fever, stiff neck, vomiting and sometimes a rash.
• After a lumbar puncture or epidural: a low-pressure headache, worse sitting or standing and eased by lying flat, with nausea and vomiting, can follow 1 to 3 days later. Contact the team who did the procedure.
• Raised pressure inside the skull: a headache that is worse lying down or on waking, with vomiting, needs urgent investigation.

Vomiting with abdominal pain

Vomiting with chest pain

Burning chest pain with vomiting is often from acid reflux or gastritis, especially after a large meal or alcohol. But chest pain with vomiting, sweating, breathlessness or pain spreading to the arm or jaw can be a heart attack, which is more likely to present this way in women, older adults and people with diabetes. Call 911 or your local emergency number. Forceful vomiting can also tear the esophagus: sudden severe chest pain after repeated retching needs emergency care.

Less common but important causes

• Diabetic ketoacidosis: vomiting, thirst, abdominal pain and fast breathing in someone with diabetes, sometimes the first sign of type 1 diabetes.
• Pyloric stenosis: projectile vomiting after feeds in babies aged about 2 to 8 weeks.
• Cyclic vomiting syndrome and cannabis hyperemesis: repeated episodes of severe vomiting; cannabis-related cases are often relieved by hot showers.
• Gastroparesis: a slow-emptying stomach, often in diabetes, causing vomiting of undigested food hours after eating.
• Inner ear disorders: vertigo from labyrinthitis or Meniere's disease.
• Kidney or liver failure, high calcium, Addison's disease and some cancers.

Dehydration: what to watch for

How doctors find the cause

A doctor will ask when it started, how often you vomit, what the vomit looks like (food, bile, blood, coffee grounds), and about diarrhea, pain, headache, fever, recent food, travel, medicines, alcohol, cannabis use, pregnancy and diabetes. They check your temperature, pulse, blood pressure and hydration, and examine your abdomen.

Most short bouts need no tests. For severe, prolonged or unexplained vomiting, tests may include blood tests (electrolytes, kidney and liver function, blood sugar), a pregnancy test, urine tests, stool samples, an abdominal ultrasound or CT scan, and sometimes an upper endoscopy.

How to treat vomiting at home

Rehydrate in small amounts

1. Wait 30 to 60 minutes after vomiting to let the stomach settle.
2. Take small sips (a teaspoon to a tablespoon) every few minutes. Increase slowly as you tolerate it.
3. Use an oral rehydration solution (ORS) from a pharmacy for children, older adults, or anyone with diarrhea as well. It replaces salts and sugar in the right balance. Water, diluted juice or clear broth are fine for healthy adults.
4. Keep breastfeeding babies; offer shorter, more frequent feeds.
5. Avoid full-strength sports drinks, sodas and fruit juice in young children, as the sugar can worsen diarrhea.

Eating again

Once vomiting has stopped for a few hours, start with small portions of bland food such as toast, crackers, rice, bananas or soup. There is no need to stick to a strict diet for days. Go back to normal eating as your appetite returns.

Medicines

• Over-the-counter options include bismuth subsalicylate for adults (not for children or teenagers, as it contains a salicylate) and antihistamines such as meclizine or dimenhydrinate for motion sickness. Follow the label dose.
• Prescription anti-sickness medicines such as ondansetron may be given by a doctor, including for children with gastroenteritis who cannot keep fluids down.
• Avoid anti-diarrhea medicines in young children, or if you have a fever or bloody diarrhea, unless a doctor advises them.

Stopping the spread

Norovirus is highly contagious. Wash hands with soap and water (alcohol gel works poorly against it), clean surfaces with a bleach-based cleaner, and stay off work or school until 48 hours after the last episode of vomiting or diarrhea.

Frequently asked questions

When should I worry about vomiting?

Seek urgent help for blood or coffee-ground material in vomit, green vomit, severe abdominal pain, a stiff neck with fever, vomiting after a head injury, chest pain, or signs of dehydration such as no urine for 8 hours. Also get care if you cannot keep fluids down for more than 24 hours.

How long does vomiting from a stomach bug last?

With norovirus and most viral stomach bugs, vomiting usually lasts 1 to 2 days, and diarrhea may continue for a few more days. If vomiting continues beyond 2 days, or you cannot keep fluids down, see a doctor.

What is the difference between regurgitation and vomiting?

Vomiting is forceful, usually comes after nausea and retching, and involves strong muscle contractions. Regurgitation is effortless: food or acid simply comes back into the mouth, typically from reflux. Effortless spit-ups after feeds are normal in many babies.

What causes pain in my side and being sick?

Side pain with vomiting is often from a kidney stone (wave-like pain going toward the groin) or a kidney infection (with fever and chills). On the right side it can be appendicitis or gallbladder disease. These need prompt medical assessment, especially with fever or worsening pain.

Why do I have a headache and vomiting after a lumbar puncture?

A small leak of spinal fluid after a lumbar puncture or epidural can cause a headache that is worse sitting up and better lying down, often with nausea and vomiting. It usually settles within a week, but contact the team who did the procedure, as treatments such as a blood patch can help.

What helps stop vomiting?

Rest your stomach briefly, then sip small amounts of fluid or oral rehydration solution every few minutes. Fresh air, avoiding strong smells, and ginger can ease nausea. A doctor can prescribe anti-sickness medicine if vomiting continues or dehydration is a concern.