15 Nausea Causes (A Comprehensive Guide by GI Doctor)

Our content is not intended nor recommended as a substitute for medical advice by your doctor. Use for informational purposes only.

Fast facts:


  • Nausea is an unpleasant sensation of being about to vomit (with or without vomiting).
  • It occurs due to abnormal motility of your stomach as a response to various diseases (nausea is not a disease of its own).
  • When you are in a car or boat, nausea is usually due to motion sickness.
  • Chronic or recurrent nausea after meals is usually due to acid reflux or GERD.
  • Psychic stress and severe pain are also very common causes of nausea.
  • See a doctor if you have severe unexplained nausea, vomiting, fever, or chest pain.

Common Causes of Nausea in Adults: 


1- Motion sickness.


Motion sickness occurs when you are in a car, boat, or any other means of transport. The symptoms include: (ref)

  • Dizziness. 
  • Sudden nausea. Vomiting can also occur.
  • Making more saliva than usual.
  • Sweating, warmth. And belching.

This is one of the most common causes of nausea.

How to manage your motion sickness?

Some tips to help you avoid motion sickness: (ref)

  • Sit in the front when you are in the car or the boat.
  • Also, fix your eyes in the direction you are moving on.
  • Avoid looking at things close to you or inside the vehicle.
  • Avoid reading and looking at your phone.

Several medicines can help prevent and treat motion sickness. Generally, these drugs work better if you take them before getting into your car or boat.

Over-The-Counter medicines for Motion sickness:

  • Dimenhydrinate (Dramamine, Trip Tone).
  • Meclizine (Antivert, Bonine)
  • Diphenhydramine (Benadryl).

Prescription medicines include: 

  • Scolopamine Patches (Scopace, Transderm Scop): this skin patch can stay for up to 3 days.
  • Promethazine (Promethegan).

Ask your doctor or nurse about the best option for your motion sickness. If you are pregnant and have motion sickness, always contact your doctor, as not all of the above medications are safe during pregnancy.

Learn more about Motion Sickness and nausea.


2- Acid Reflux and GERD:


Acid reflux is the regurgitation of the acid content of your stomach into the esophagus. Does acid reflux occur due to the? Loosening? of the sphincter between the lower part of the esophagus and stomach.

When symptoms become bothersome to you, doctors call the condition? Gastro-Esophageal Reflux Disease or GERD. 

Symptoms of GERD and ACID Reflux: (ref)

  • Heartburn: burning feeling in your chest.
  • Regurgitation: of acid or food into your throat or your mouth.
  • Nausea or vomiting.
  • Unexplained cough, bad mouth odor.
  • Trouble swallowing.
  • Having a raspy voice and a sore throat.

Learn more about GERD AND Nausea.


3- Gastroenteritis / Food poisoning.


Infection with gut bugs such as norovirus or rotavirus causes inflammation of your stomach and intestines (gastroenteritis). Also, eating food contaminated with viruses, bacteria, chemicals, or toxins (food poisoning) can lead to gastroenteritis. 


How to suspect gastroenteritis/food poisoning?

  • Acute onset nausea, diarrhea, colics, and epigastric pain.
  • The condition can be associated with fever.
  • Diarrhea is usually severe and can be yellowish watery, or greenish.
  • Vomiting can occur with nausea.
  • Malaise or generalized fatigue and body aches can occur.
  • In severe cases, dehydration can lead to confusion, dizziness, and decreased urine.

Gastroenteritis is usually a self-limiting condition within a few days. Consult your doctor if your symptoms last for more than three days or if you have severe symptoms, and you suspect food poisoning.

Learn more about

4- Severe pain.


Acute and chronic pain conditions can cause nausea (ref). If you have diseases that cause chronic pain or a sudden severe painful condition, this can lead to nausea or vomiting.

Examples of acute and chronic painful conditions that can lead to nausea (or vomiting):

  • Kidney (loin) pain: due to stones or gravel inside your kidney or ureter.
  • Pancreatitis [acute and chronic]: severe pain in the upper central part of your abdomen due to inflammation of the pancreas (mainly due to obstruction of its duct).
  • Cholecystitis [acute and chronic]: acute cholecystitis pain is usually very severe, associated with intense nausea and maybe vomiting.
  • Heart attack (chest pain): the pain from a heart attack occurs in the chest or the upper part of the abdomen. And it can be associated with nausea or vomiting.
  • Severe trauma: any severe trauma to your bones or internal organs can lead to nausea or vomiting.
  • Postoperative pain: postoperative nausea or vomiting is very common. Pain is the most common cause of postoperative nausea.
  • Chronic cancer pain.
  • Migraine headaches (see later).

CAUTION: Nausea and severe chest or stomach pain can indicate a dangerous health condition such as a HEART ATTACK. Please consult your doctor immediately if you have no explanation for your severe pain.


5- Psychic stress, anxiety, and Reactions to certain smells.


Psychic stress and anxiety can cause nausea by triggering? Fight or flight response? The response includes a rush of hormones and neurotransmitters that prepares your body to cope with stressful situations. 

But this? A rush? hormones can affect your digestive system, causing: (ref).

  • Nausea or vomiting.
  • Colics, diarrhea, or painful spasms in the bowel.

Learn more about stress, anxiety, and nausea.

Also, certain smells can trigger nausea or even vomiting. The reaction to smells is greatest among females, especially pregnant females. (discussed below)


6-Pregnancy (morning nausea).


Nausea is one of the most common complaints during pregnancy. Up to 70% of pregnant women feel nauseous at some point during pregnancy (ref). It is thought to be due to increased pregnancy hormones such as estrogen and progesterone.

Nausea (and vomiting) during pregnancy are more common in the morning (morning sickness). Fortunately, researchers found a decreased risk of miscarriage in women who have nausea with pregnancy (ref).

Nausea (& vomiting) during pregnancy is more common with (ref) :

  • Younger women.
  • First-time pregnancy.
  • Obese women.
  • Non-smokers!
  • Women with a previous history of motion sickness.
  • Women with a history of nausea due to oral contraceptive pills (ref).

7- Medications.


One of the most common causes of nausea is the medications you intake. Many groups of medications can potentially cause nausea. 

Before thinking of the worst, review any medications you intake recently (and also your chronic medications). 

Even non-prescription drugs (over-the-counter) can be the cause of your nausea. They include(ref) :

  • Analgesics and anti-gout medications.
  • Drugs are used to treat heart diseases and hypertension.
  • Cancer chemotherapy medications.
  • Oral contraceptive pills
  • Some antibiotics.
  • Medications like antiparkinson drugs and anticonvulsants are used to treat neurological disorders.
  • Anti-asthma Medications
  • Radiation therapy.
  • IBD medications.
  • Over-dose of vitamin supplements (common nowadays). 

The complete list of drugs causing nausea (or vomiting) (ref): 


Medications causing nausea Examples
1- Analgesics: medications used to treat headaches and pain Aspirin.Other NSAIDs such as Ibuprofen, ketoprofen.Anti-gout medications.
2- Drugs for heart diseases: Digoxin (especially over-dose).Beta-blockers (such as bisoprolol).Calcium channel blockers (as Amlodipine).Other antihypertensives and anti-arrhythmia medications.Diuretics
3- overuse of vitamin supplements (hypervitaminosis). Vitamin D overdose.Vitamin A overdose.
4- Cancer chemotherapy. Severe nausea and vomiting, especially with: Cisplatinum.Dacarbazine.Nitrogen mustard. Others cause moderate to mild nausea: Methotrexate.Cytarabine.Etoposide.Fluorouracil.Tamoxifen.
5- Hormonal preparations/therapies Oral contraceptives.Anti-diabetic drugs.
6- Antibiotics / Antivirals Erythromycin.Tetracycline.SulfonamidesAnti-TB drugs.Acyclovir.
7- IBD (Crohn’s & Ulcerative Colitis) medications Sulfasalazine.Azathioprine.
8- CNS druAntiparkinsonian Nian drugs.Anticonvulsants (& epilepsy) drugs.
9- Anti-asthma drugs: Theophylline


8- Too much alcohol drinking.


Too much alcohol drinking causes bad effects on your gut, including nausea and throwing up. This is due to (ref):

  • Alcohol is an irritant to your stomach.
  • It can cause dehydration and electrolyte imbalance.
  • Central effects on your brain (hangover).

9- Migraine.


Migraine is a common condition characterized by severe headache, light, and sound sensitivity, and maybe nausea and vomiting (ref).

Nausea is one of the most distressing symptoms of migraines and headaches. Between 20% and 50% of people with recurrent migraines have nausea or vomiting with some or all migraine episodes (ref).

Nausea with migraines can be controlled by over-the-counter or prescription medications. Also, diet and diet control and some alternative medicine techniques can help. 

Learn more about the management of migraine nausea here.

10- Ear problems.

Inflammation inside your ear can cause nausea, most commonly: (ref), (ref)

  • Inflammation inside the inner ear (Vestibular neuritis and Labyrinthitis)
  • Inflammation inside the middle ear (Otitis media)

Vestibular neuritis symptoms include:

  • Vertigo: a sense of whirling and loss of balance. Usually acute onset.
  • Nausea and vomiting.
  • The severe condition may affect your gait (becoming unable to stand or walk).
  • NO affection of hearing in pure vestibular neuritis.

Labyrinthitis is the same as vestibular neuritis, Plus the involvement of hearing affection (hearing loss or abnormal hearing sensations such as tinnitus).

Also, Middle ear inflammation can cause nausea and vertigo. Consult your doctor about your nausea related to vertigo, especially if: (ref)

  • You experience acute onset, persistent vertigo.
  • Vertigo and nausea are associated with severe headaches.
  • Vertigo and nausea are associated with unilateral numbness, weakness, or speech abnormality.
  • The onset of your nausea and vertigo starts above the age of 60.

11- Gut obstruction (gastric outlet or small intestinal obstruction).

Obstruction of your stomach due to abnormalities of the sphincter connecting it to the duodenum and small intestine is called? Gastric Outlet Obstruction). (ref)

Also, obstruction of your intestines for any reason will result in severe nausea, distension, vomiting, and constipation. (ref)

Please consult your doctor immediately if you develop acute, persistent nausea, vomiting, severe abdominal distension or bloating, and constipation.

12- Gastroparesis (especially if you have diabetes mellitus).

Gastroparesis means delayed emptying of your stomach in the absence of Mechanical gastric obstruction [ref]. Gastroparesis results in chronic or recurrent nausea and other symptoms such as: 

  • Early satiety even with small amounts of food eaten.
  • Nausea may progress to vomiting.
  • Bloating: a sense of fullness.
  • Belching: expelling gas loudly from your stomach through the mouth.

The most common causes of Gastroparesis are:

  • Diabetes mellitus: due to damage to the nerves controlling your stomach’s motility.
  • Some medications, such as (ref):
    • Calcium channel blockers (used in hypertension and heart medications).
    • Narcotics.
    • Tricyclic Antidepressants.
    • Progesterone (present in Birth control pills).
    • Lithium & others.
  • Stomach or intestinal surgery.
  • In some patients, the cause is unknown.

Gastroparesis diagnosis can be difficult, and your doctor may need some tests to assess and diagnose the condition. Consult your doctor if you have diabetes mellitus or using any of the above medications.

13- Cholecystitis.

Cholecystitis is the inflammation of your gallbladder. This inflammation may be due to stones (calcular cholecystitis) or other causes (Non-calcular cholecystitis). 

Cholecystitis can be acute with severe upper abdominal pain (to the right), severe nausea, vomiting, and maybe fever. Also, it can become chronic with recurrent acute attacks of Rt upper abdominal pain, nausea, or vomiting.

The pain from cholecystitis can be referred to as the back between shoulder blades or to the right shoulder.

Risk factors for developing cholecystitis and gallstones include: (ref)

  • Being female.
  • Obesity.
  • Being age 40 or older.
  • High-fat diet or low-fiber food.
  • Rapid weight loss.
  • Being pregnant or taking oral contraceptive pills
  • Diabetes mellitus and blood diseases such as sickle cell anemia or leukemia.

14- irritable Bowel Syndrome.


Irritable bowel syndrome is a functional intestinal disorder characterized by recurrent abdominal pain related to defecation and change in stool frequency and form.

Nausea is not a cardinal feature of irritable bowel syndrome but is frequently noticed with IBS. A study revealed that people with IBS had a 2.7-fold chance of developing nausea than those without IBS (ref).

Also, it is known that people with IBS have other functional GI disorders, such as functional dyspepsia and GERD. This increases the chances of developing nausea and IBS.

If you have IBS and Nausea, talk with your doctor about its possible cause and relation to IBS. 


15- Other causes of nausea inside your abdomen.


A variety of diseases in your gut can cause nausea. We discussed GERD, Gastroparesis, intestinal obstruction, and gastric outlet obstruction in detail above.

Other Gut diseases causing nausea include: (ref)

  • Other functional gut diseases such as Non-ulcer dyspepsia, chronic intestinal Pseudo-obstruction, and Chronic constipation can cause nausea.
  • Pancreatic cancer.
  • Inflammatory intra-peritoneal diseases.
  • Pancreatitis (acute and chronic).
  • Hepatitis, especially acute hepatitis such as Hepatitis A virus.
  • Crohn’s disease.
  • Decreased blood supply to the intestine or colon (Mesenteric ischemia).
  • A condition called Retro-peritoneal fibrosis (Or any retro-peritoneal masses).
  • Intra-abdominal cancers or Metastases.

16- Causes inside your brain.


Nausea and vomiting centers lie inside your brain; many brain diseases can lead to nausea and vomiting through the affection of these centers. Migraine is thought to cause nausea through the affection of the vomiting centers in the brain.

Brain diseases that are associated with nausea include: [ref]

  • Migraine [discussed before].
  • Any diseases causing an increase in the pressure inside your skull (intracranial pressure):
    • Brain tumors.
    • Brain hemorrhage or infarction (stroke).
    • Brain infections such as abscess meningitis.
    • Hydrocephalus and congenital malformations of the brain.
  • Seizures disorders such as epilepsy.
  • Brain irradiations (during treatment of brain malignancy or metastases).
  • Psychiatric disorders include depression, psychogenic vomiting, anorexia nervosa, and bulimia nervosa).



Other causes may include: (ref)

When to see a doctor for your nausea?


Call your doctor or nurse about your nausea if (2)

  • Your nausea lasts over a day or two with no obvious cause.
  • You have very severe nausea, or you have associated vomiting.
  • You have intense chest or abdominal pain.
  • Have reddish or blackish stool (blood in stool).
  • You have a fever of more than 38 C  (101 F).
  • You have a severe headache or stiff neck.
  • Your nausea is not responding to usual treatments.

MORE: 11 Causes of Sudden Nausea That Comes and Goes In Waves.


When should I be concerned about nausea?

Nausea is a sensation many of us have felt at one point or another. It can be a result of various triggers, from a dodgy meal to a pounding headache. But if this feeling lingers for more than several days, or if it’s paired with intense discomfort, dehydration, or unexpected weight changes, it might be time to chat with a medical expert. Also, if there’s a chance it’s related to a potential pregnancy or a medication reaction, it’s wise to get some professional input.

Why do I feel nauseous all the time for no reason?

Constant queasiness can be both baffling and unsettling. There’s a myriad of potential culprits, from stomach-related issues and pounding headaches to certain meds, the possibility of pregnancy, or even mental factors like heightened anxiety or stress. If nausea seems to be your constant companion without a clear trigger, it’s a good idea to have a sit-down with a healthcare provider to pinpoint the cause.

How long does nausea normally last?

Nausea’s staying power can vary based on what’s causing it. If it’s due to a bad meal or a fleeting stomach issue, it might stick around for a few hours to a day or two. If it’s a reaction to a medication, it could hang around as long as you’re taking that particular drug. But if you’re dealing with a lingering sense of nausea and can’t pinpoint why, it’s a smart move to touch base with a medical professional to get to the root of the issue.