Vomiting: Read It, and When to Go In

Key takeaways

Vomiting is not an illness but a sign. What decides how dangerous it is, is what comes with it — and vomiting on its own, without loose stools, calls for thinking wider than one meal.
Look at the vomit first: according to NHS, vomiting blood, vomit that looks like coffee grounds, and green vomit are all on the list of reasons to call for an ambulance.
If not a single mouthful of water stays down, stop caring for it at home and go to a medical facility. Recognising dehydration and how to replace fluids already have two articles of their own on this site.
A few episodes of vomiting with nothing staying down is more worrying than many episodes in someone who is still drinking and still passing urine normally. The number of episodes is not the measure.
According to NHS, anti-sickness medicine is something a doctor prescribes when they judge it necessary. Do not buy it yourself to silence the vomiting while nobody yet knows why it is happening.
Someone with diabetes who is vomiting and cannot keep food or fluids down: according to CDC, go to emergency care now — and keep taking insulin and medicines as usual, do not stop them on your own.

Vomiting is a sign, not an illness. What decides how dangerous it is, is what the vomit looks like and what comes with the vomiting. Vomiting together with loose stools is usually an intestinal infection; vomiting on its own calls for thinking wider than one meal.

Recognising it: look at the vomit first

According to CDC, vomiting together with loose stools, nausea and stomach pain is the usual set of symptoms of norovirus, and most people get better within one to three days. Recognising dehydration already has its own article on this site.

According to NHS, vomit containing blood may be anything from bright red to brown or black, thin or thicker, or may look like coffee grounds.
Green vomit: according to NHS, green vomit in an adult, or yellow-green or green vomit in a child, is on the list of reasons to call for an ambulance.
A baby vomiting forcefully, in a jet, and then wanting to feed again straight away. According to MedlinePlus, forceful projectile vomiting is a sign of pyloric stenosis, which usually begins in the first weeks after birth.
Not a single mouthful of water staying down: at that point stop caring for it at home, whatever the vomit looks like.

The commonest confusion: a baby bringing up a little milk after a feed and then playing normally is quite different from forceful projectile vomiting — the latter needs to be seen.

Vomiting without loose stools: think wider than one meal

When vomiting comes on its own, the cause usually lies outside the gut. The signs that come with it tell you which direction, and each direction has its own article:

After a blow to the head: according to CDC, repeated vomiting is a danger sign after a traumatic brain injury.
A sudden severe headache, or a stiff neck and dislike of light: pointing towards meningitis.
Abdominal pain in one place that keeps increasing: pointing towards appendicitis, pancreatitis, gallstones.
A crushing chest pain spreading to the arm, back, neck or jaw: according to NHS, this may be a heart attack.
A distended abdomen that does not go down, with neither wind nor stool passing: according to MedlinePlus, a sign of bowel obstruction.

What to do now

Drink in very small sips and then wait, then build up gradually. According to NHS, while you feel sick drink in small sips, and do not drink a large amount with a meal.
Rest somewhere with fresh air: according to NHS, breathing fresh air helps with nausea.
Eat again once fluids are staying down. According to NHS, eat when you can, have smaller meals more often, avoid greasy or spicy food, and do not lie down straight after eating.
A breastfed baby carries on feeding as usual; according to NHS, do not make up formula more dilute than normal.
If someone is drowsy, lie them on their side and stay with them, and give nothing to eat or drink because of the risk of choking. According to NHS, in their guidance on alcohol poisoning, only give sips of water if the person is awake, can swallow and is not vomiting.
Write it down: when the vomiting started, how many episodes, what the vomit looked like, when they last passed urine, what medicines they are on.

Things you must NOT do

Do NOT buy anti-sickness medicine yourself. According to NHS, this is something a doctor prescribes when they judge it necessary. The vomiting is the very sign a doctor uses to find the cause.
Do NOT make the person vomit more, do not put fingers down the throat — according to NHS, do not try to make the person sick.
Do NOT buy antibiotics yourself. According to CDC, antibiotics do not help treat norovirus because they kill bacteria, not viruses.
Do NOT stop treatment medicines on your own. According to CDC, people with diabetes who are ill should carry on taking insulin and their medicines as usual.

Three groups whose threshold is far lower

People with diabetes: according to CDC, vomiting with nothing staying down is the point at which to go to emergency care.
Pregnant women: according to NHS, vomiting a great deal and being unable to keep food down should be mentioned at once to your obstetrician or midwife; the severe form usually needs treatment in hospital. We do not take on maternity care.
Older people and young children: they become dehydrated faster while the signs are fainter. According to NIDDK, a change in mental state — being irritable or lacking energy — is a reason to tell a doctor straight away.

When you must go to hospital

GO TO EMERGENCY CARE or call 115 (the emergency number in Vietnam) NOW if: vomiting blood, or vomit that looks like coffee grounds; green or yellow-green vomit; repeated vomiting after a blow to the head; a sudden severe headache; a stiff neck with dislike of light; sudden severe abdominal pain, or pain in one place that keeps increasing; a crushing or heavy chest pain spreading to the arm, back, neck or jaw; marked difficulty breathing; a distended abdomen that does not go down, with neither wind nor stool passing; not a single mouthful of water staying down; no urine passed for hours; drowsy, hard to wake, confused, seizures; skin, lips or tongue blue, grey or mottled; suspicion that something poisonous has been eaten or drunk; a baby vomiting forcefully in a jet and then wanting to feed again; a breastfed baby refusing the breast completely; someone with diabetes vomiting and unable to keep food or fluids down. — BE SEEN WITHIN 24–72 HOURS if: still able to drink but the vomiting is not easing, the fever is not coming down, weight is being lost; the vomiting began after a new medicine; or the person is a young child, an older person, a pregnant woman, or someone with heart, kidney or liver disease, diabetes or a weakened immune system — this group should not wait to see whether it settles. And if there are still signs of dehydration despite replacing fluids correctly: be seen the same day.

Put plainly: the cause of an episode of vomiting cannot be found at home. We offer a remote consultation by video call when you are not sure whether hospital is needed; a doctor coming to the house to take a history, examine, and say clearly which cases must be admitted; and a nurse giving prescribed fluids. A remote consultation is not for anyone who is drowsy or having seizures — with a sign in the box above, go in first and ring afterwards.

This article passes on the recommendations of public health bodies — sources: the US CDC, the UK NHS, NIDDK at the NIH, and MedlinePlus — and does not replace being examined. Citing CDC here does not imply that CDC endorses Y Te Xanh or our services.

Need personalised advice for your loved one? Call our hotline 094 368 81 15 (24/7) — calling to ask a question or to book costs nothing. GreenCare has doctors who come to examine, nurses who carry out doctor's orders (injections, infusions, dressing changes), remote consultation by video call, and a review of the medicines you are taking; an in-depth remote consultation, or any one after the first, is a paid service. For children we take examination and acute care only — not long-term care at home, and not newborns or expectant mothers. We confirm we have staff in your area and provide transparent pricing before we begin.

Sources

NHS — Feeling sick (nausea)
MedlinePlus — Nausea

Frequently asked questions

How long can vomiting go on before I need to be seen?

According to NHS, vomiting usually settles within one to two days, and vomiting that goes on for more than two days is a reason to contact a health professional. According to MedlinePlus, get in touch straight away if you have been vomiting for more than a day, or have been unable to keep any fluid down for half a day or more. But time is not what decides it: someone who is still drinking and still passing urine normally can be watched at home, while someone who cannot keep a single mouthful down needs to be seen now even if the vomiting only started this morning.

Should I take an anti-sickness medicine to feel better?

Ask a doctor or pharmacist first. According to NHS, anti-sickness medicine is something a doctor prescribes when they judge it necessary, not something to buy yourself. The reason is not only the safety of the drug: the vomiting is the very sign a doctor uses to find the cause, so silencing it while nobody yet knows why it is happening hides the thing that needs to be seen — particularly when the cause is in the group that needs early intervention, such as bowel obstruction or appendicitis. What makes someone feel better straight away is drinking in very small sips and then waiting, and resting somewhere with fresh air.

Vomiting without loose stools — is it something I ate?

Not necessarily, and this is exactly where people guess wrong. Vomiting with loose stools is usually an intestinal infection, while vomiting on its own often has a cause outside the gut: a blow to the head, an infection of the nervous system, a condition in the abdomen needing surgery, bowel obstruction, heart disease, or a complication of diabetes. So look at what comes with it rather than only at the number of episodes: a severe headache, a stiff neck, abdominal pain in one place that keeps increasing, chest pain, a distended abdomen with neither wind nor stool passing — each of these changes what needs to be done.

Does a baby with projectile vomiting need to go to hospital?

Yes, have the baby seen. According to MedlinePlus, forceful projectile vomiting is a sign of pyloric stenosis — a narrowing where the stomach joins the small intestine — usually beginning in the first weeks after birth; the baby is still hungry after vomiting so wants to feed again, and may lose weight or fail to gain it. MedlinePlus states that the treatment is surgery to widen the narrowed part, so this belongs to a medical facility: it can be neither diagnosed nor treated at home. A breastfed baby who refuses the breast completely should go in now.

What should someone with diabetes do if they are vomiting?

Lower the threshold a great deal. According to CDC, vomiting with nothing staying down is one of the signs that mean going to emergency care now, together with difficulty breathing and fruity-smelling breath, because that may be ketoacidosis. CDC advises carrying on with insulin and medicines as usual while ill, drinking enough fluids, and ringing a doctor straight away if a urine test shows ketones. Do not stop medicines because you are worried about vomiting them up — ring the doctor who prescribed them.

What should I take with me to emergency care for vomiting blood?

Take all the medicines you are on, including ones prescribed long ago rather than only what you have taken today — according to NHS, take all your current medicines with you when you go to emergency care for vomiting blood. Say clearly what the vomit looked like, when the vomiting started, how many episodes there have been, and whether the stools have been black. And according to NHS, do not drive yourself: get someone else to take you or call for an ambulance.