Nausea is an unpleasant sensation of discomfort or unease in the stomach (queasy stomach), accompanied by an urge to vomit. Nausea often precedes vomiting.
Nausea is not a disease in itself,1 but rather a non-specific symptom, i.e. there are several possible causes, including motion sickness, stomach infection, migraine, certain odors, food poisoning, gallbladder disease, very intense pain, early pregnancy, indigestion, certain viruses, chemical toxins and emotional stress (fear).
According to DiagnosisPro, there are over 700 causes of nausea,2 and those are just due to poisoning! This article focuses on the most common causes.
Morning sickness, also known as nausea gravidarum, refers to nausea and vomiting during pregnancy. We have a detailed article on morning sickness, which affects more than half of all pregnancies and we also have an article containing tips to minimize morning sickness.
Causes of nausea are nearly always due to problems in any of these three parts of the body: the brain and spinal fluid, the pelvic and abdominal organs, and the inner ear.4
Brain and spinal fluid
Many diseases and conditions related to the brain or spinal fluid have nausea as one of their many symptoms, including:
Pelvic and abdominal organs
The most common pelvic/abdominal diseases and conditions that have nausea as one of their symptoms are:
- Blocked/stretched stomach
- Blocked/stretched intestine
- GERD (gastroesophageal reflux)
- Stomach irritation
- Irritation of the intestinal lining
- Kidney disease
- Gallbladder disease
- Gastroenteritis – usually caused by a virus
Patients with problems with their inner ear may experience nausea, as well as vertigo – a sensation of things moving around you or spinning. Inner-ear conditions include:
- Motion sickness – examples include air sickness, car sickness, sea sickness, train sickness, feeling “whoozy” after funfair rides, and being an astronaut in zero gravity.
During their adaptation to weightlessness, approximately half of all astronauts experience nausea caused by motion sickness,11 visual illusions and disorientation. It is known as space adaptation syndrome or space sickness.
Although medications are available, NASA prefers the astronaut to wait it out for a couple of days.
- Labyrinthitis – an inner-ear infection, usually caused by a virus. The patient’s hearing and balance may be affected.
- Benign positional vertigo – patients develop a sudden sensation of spinning, typically when moving their head. It is a common cause of vertigo.
Several psychological factors can induce nausea. Some people find that they experience nausea just by watching somebody else vomiting.
Medical students may experience nausea, dizziness and even fainting when witnessing an autopsy for the first time.
The following mental illnesses/conditions usually have nausea as one of their symptoms:
A Norwegian study involving more than 62,000 people found that nausea, which affects about 12% of people in the community, is a common symptom of anxiety and depression.6
Tone Tangen Haug, M.D., Ph.D., of Haukeland University Hospital in Norway and team reported in the journal General Hospital Psychiatry that patients with anxiety and depression frequently present with gastrointestinal symptoms such as nausea and abdominal discomfort as their main problem when visiting the doctor.
The researchers wrote “Functional gastrointestinal disorders are strongly related to anxiety and depressive disorders with a lifetime prevalence of 80-90% in samples from clinics of gastroenterology.”
Nausea and vomiting, which are serious side effects of cancer therapy, need to be controlled to maintain both the patient’s treatment and quality of life.8
The most common causes of nausea for cancer patients are:
- Chemotherapy – how often and/or severe symptoms are depend on the type of drug used, its dosage, whether it is administered with other medications, how often it is given, how it is administered, and the individual patient.
- Radiation therapy – especially therapy that targets the brain, liver or gastrointestinal tract. The likelihood of nausea increases as the radiation dosage rises.
Nausea may also be caused by a tumor blocking the bowel.
The following factors may increase a cancer patient’s risk of developing nausea and vomiting:
- Nausea and vomiting in previous chemotherapy sessions were severe and frequent
- Female patients have a significantly higher risk of severe nausea during cancer treatment
- The patient has constipation
- He or she is taking certain medications, such as opioids
- The patient is very anxious
- There is an infection or blood poisoning
- The patient has kidney disease
- There is a fluid/electrolyte imbalance – too much blood calcium, dehydration, or excess fluid in body tissues
In most cases nausea is a temporary symptom that goes away on its own. Do not be alarmed if it is accompanied by vomiting; it means that your body is trying to get rid of whatever made you feel ill.
However, sometimes nausea (and vomiting) may be a sign of an underlying disease or something serious, such as a blockage or kidney stones.3
You should check with your doctor1 if:
- Abdominal pain is severe
- There is blood in the vomit
- You are also vomiting, and the vomiting persists for more than 24 hours
- You have a headache
- You have a stiff neck
- Your urine is dark, you are urinating infrequently, and your mouth is dry – these are signs of dehydration.
Children with nausea and vomiting have a higher risk of dehydration than adults, because they do not usually detect or communicate the symptoms.
If your child has nausea, vomiting, dry lips, dry mouth, sunken eyes, is breathing rapidly and has an accelerated heart beat, he or she is probably dehydrated and should be seen by a doctor. Additional signs include infrequent urination and a sunken fontanelle (the soft area on top of the infant’s head).
Medications for the treatment of nausea and/or vomiting are called antiemetics. There are several OTC (over-the-counter, no prescription required) antiemetics.
This medication may help in cases of gastroenteritis, stomach upset and also diarrhea. Examples of brand names include Pepto-Bismol and Kaopectate.
If you are allergic to aspirin or other salicylate medicines you should not take bismuth subsalicylate. Children under 12 years of age should not take bismuth subsalicylate, and neither should adolescents (aged 12 to 18) who have chickenpox or the flu.
Side effects are rare, but may affect older adults or patients with underlying health problems. There is a small risk of darkened stools or tongue, constipation and tinnitus (ringing in the ears).
Antihistamines dull the inner ear’s ability to sense motion, and may alleviate symptoms of nausea caused by motion sickness. Examples include dimenhydrinate (Dramamine) and meclizine hydrochloride (Dramamine Less Drowsy). They work best if taken beforehand, e.g. if you get car sick, take it just before your trip.10
If you are taking sedatives, muscle relaxants or sleeping pills, check with your doctor before taking antihistamines.
Side effects may include drowsiness/sleepiness, dry eyes, or dry mouth.
Make sure you read the directions on the drug facts label and follow the instructions regarding dosage and how often you should take the medication. If you are not sure talk to the pharmacist or your doctor.
Many of the causes of nausea (and vomiting) are outside the patient’s control. However, the following self-care tips offered by the Department of Health and Human Services, Tasmania, Australia, may help you feel better:7
- Anti-nausea medications work better if taken regularly than occasionally
- If you cannot hold your medication down, tell your doctor
- Nausea and constipation often go together. Tell your doctor if you are constipated
- Fresh and cool air can help alleviate symptoms of nausea. Open a window, use a fan or go outside for a while
- Ginger is known to relieve nausea symptoms. You can take it either in tea or crystals
- Try to make sure there is always some food in your stomach. Have several small meals during the day. However, if you are also vomiting, avoid solid food until symptoms have gone9
- Sit upright after eating. If you have to lie down, it helps if the head of your bed is raised.