Nausea and Vomiting

AAbout Your Symptoms & ED Evaluation

Nausea is the feeling that you may throw up. Vomiting is a reflex run by the brain. Nerves carry signals from the gut to the brain. Some stomach viruses make the gut release a chemical called serotonin. That chemical starts the signal to vomit.

This fast nerve signal is why vomiting may start before diarrhea. Diarrhea takes longer as the gut lining changes. This order can be normal for a stomach infection. It does not always mean the illness is getting worse.

Many things can cause vomiting. They include infections, pregnancy, migraine, medicines, cannabis, and problems in the belly or brain. Your history and exam guide the workup. Not everyone needs the same tests. Tests also cannot find every cause early. Return if symptoms are new, changing, or worse.

FFirst Steps & Evidence-Based Home Care

1. Replace fluid slowly

Take small, frequent sips. Use a drink labeled “oral rehydration solution.” Guideline examples include Pedialyte and CeraLyte. These drinks have the right mix of water, sugar, and salts. Soda, sports drinks, and apple juice do not.

For teens and adults who weigh at least 30 kg and have mild or moderate fluid loss, the guideline range is 2 to 4 liters at first. This is not a personal daily fluid goal. Follow your discharge plan. This matters if you have heart or kidney disease or were told to limit fluids. IV fluid is used for severe fluid loss or when drinking does not work.

2. Eat when you can

Return to normal food as soon as it feels tolerable. There is no evidence that people need to avoid solid food for 24 hours or stay on the BRAT diet of bananas, rice, applesauce, and toast.

3. Do not assume antibiotics will help

Most short stomach infections are caused by viruses. Antibiotics do not help them. Antibiotics that are not needed can cause harm.

If cannabis may be involved

Heavy cannabis use can cause repeated vomiting. This is called cannabinoid hyperemesis syndrome. Hot showers or baths may give brief relief. Stopping cannabis is what prevents the cycle from continuing. A follow-up clinician can check for other causes of repeated vomiting.

If symptoms began after a GLP-1 medicine

Nausea and vomiting are common after starting or raising the dose of a GLP-1 medicine. Small meals and careful fluid intake may help. Call the prescriber if symptoms are severe or do not stop. Long bouts of vomiting or diarrhea can cause fluid loss and kidney injury. Do not change the dose on your own. Follow the emergency warnings below.

TTimeline & Expected Recovery Course

Norovirus is a common stomach virus. It often lasts 2 to 3 days. About three out of four people recover within three days. The gut can repair the cells harmed by the virus.

Not every case follows that short course. Vomiting can come back with some health problems or cannabis use. Arrange follow-up if it lasts more than 48 to 72 hours. Also follow up if drinking is still hard or a new symptom appears. Return to the ER if symptoms last 5 to 7 days, get worse, or get better and then worsen.

EEmergency Red Flags: When to Return Immediately

Return to the emergency department if any of these happen:

• You cannot keep any fluids down for more than 12 to 24 hours.
• You pass very little or very dark urine. You feel dizzy when standing, have a very dry mouth, or have a fast heartbeat.
• There is blood in the vomit, or the stool is bloody or black.
• You have severe belly pain, a high fever, confusion, or unusual sleepiness.
• A baby or child has vomit that may contain bile. It may look yellow or green. Do not use the exact shade to decide that it is safe. In an infant, this can be a sign of a blocked bowel and needs care now.
• Vomiting comes with a severe headache, new weakness, new numbness, trouble speaking, chest pain, or heavy sweating.
• Symptoms last 5 to 7 days, keep getting worse, or improve and then become worse again.

This list does not include every emergency. Return to the emergency department for any severe, new, or rapidly worsening symptom.

If drinking the right fluid is safe and working, no IV does not mean the care was worse. The goal is the right care for the amount of fluid loss. More treatment is not always better.

If this guide is for a baby or child

In babies 2 to 8 weeks old, forceful vomiting that keeps getting worse can be a warning sign. In children 6 to 36 months old, watch for waves of bad belly pain with vomiting and bloody or slimy stool. A bulging soft spot, growing head size, vomiting at night, or unusual sleepiness also needs urgent care.