Why Do I Feel Nauseous?

If your stomach is churning without an apparent cause like gastroenteritis ("stomach bug") or pregnancy, you may wonder, "Why do I feel nauseous?"

When nausea strikes, you quickly start retracing your steps: What you ate, if you've been around anyone sick, and, for some people, when your last period was. Aside from a stomach bug and pregnancy, many other things cause nausea.

Here are the less typical causes of nausea, as well as how to prevent and relieve nausea.

1. Anxiety

Anxiety causes fear and uneasiness in response to stress, like an upcoming presentation or test. Some people develop generalized anxiety disorder (GAD) if anxiety is long-term.

Your gut has millions of nerve cells that communicate with your brain. Anxious thoughts may impact the nerve cells in your gut. As a result, you may develop nausea.

Anxiety may cause other gastrointestinal (GI) symptoms like:

• Abdominal pain
• Bloating
• Vomiting

Cognitive behavioral therapy (CBT) and anti-anxiety medicines help treat GAD. For example, CBT teaches you how to reduce anxious thoughts, which may treat nausea.

2. Cannabinoid Hyperemesis Syndrome

Cannabis, which some people use to relieve nausea, may have the opposite effect. Cannabinoid hyperemesis syndrome (CHS) causes severe abdominal pain, nausea, and vomiting.

Some research suggests prolonged cannabis use inactivates specific receptors in your brain, leading to nausea.

You can alleviate CHS by stopping cannabis use. Limited evidence suggests that capsaicin, a component in chili peppers that makes your mouth feel hot, may treat CHS. Applying topical capsaicin to your abdomen produces heat, which may alleviate nausea.

3. Cyclic Vomiting Syndrome

Cyclic vomiting syndrome causes repeated, sudden attacks of severe nausea, tiredness, and vomiting. A single episode can last from one hour to 10 days. Cyclic vomiting syndrome is more common among children than adults.

Experts say cyclic vomiting syndrome is a related to migraines. People with cyclic vomiting syndrome often have a family history of migraines.

Common triggers of cyclic vomiting syndrome include:

• Alcohol
• Allergies
• Certain foods
• Excitement
• Exhaustion
• Extreme temperatures
• Fasting
• Infections
• Lack of sleep
• Menstruation

A healthcare provider may prescribe anti-nausea medicines to treat cyclic vomiting syndrome. You may prevent nausea and vomiting by avoiding and treating triggers.

4. Digestive Reasons

You may develop nausea if there's a blockage in your digestive system or if something irritates your gut. Some of nausea's most common digestive causes include gallbladder disease, gastroesophageal reflux disease (GERD), and gastroparesis.

Gallbladder Disease

Your gallbladder stores bile, which your liver makes to help digest fat. When you digest food, your gallbladder releases bile through a tube to your small intestine.

Sudden right-side abdominal pain after a heavy meal is a classic sign of a gallbladder attack. The pain usually strikes when gallstones, or hard particles, block the tube carrying bile to your small intestine. 

Sometimes, a gallbladder attack causes nausea and vomiting. Consult a healthcare provider right away if you have nausea and vomiting during or after a gallbladder attack. Those symptoms may signal an infection or inflammation in your gallbladder, liver, or pancreas.

A healthcare provider may advise surgical removal of your gallbladder if you often get gallbladder attacks. Bile can travel to your small intestine in many ways, so you do not need your gallbladder to live.

Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) causes your stomach contents to travel into your esophagus. Your stomach contents are highly acidic, which irritates your esophagus. As a result, you may develop heartburn.

GERD may cause nausea if you taste your stomach contents in the back of your mouth. Research has found that some people with GERD have bouts have nausea and vomiting.

You can prevent or alleviate GERD symptoms by trying the following remedies:

• Avoid eating too close to bedtime.
• Eat small meals.
• Limit alcohol and acidic, fatty, and spicy foods.
• Maintain a healthy body weight.
• Wear loose-fitting clothing.

Gastroparesis

Gastroparesis is a digestive disorder that slows food movement from the stomach to the small intestine. It's unclear what causes gastroparesis. Gastroparesis may occur if something disrupts nerve signals to the stomach. Often, the disorder is a complication of diabetes.

In addition to nausea, gastroparesis may cause symptoms like:

• A swollen abdomen
• Abdominal pain
• Feeling full quickly while eating
• Low blood sugar in people with diabetes
• Unintentional weight loss
• Vomiting

Controlling your blood sugar may alleviate gastroparesis symptoms if you have diabetes. Eat small meals, spread evenly and frequently throughout the day, instead of three large meals to prevent flares.

Other gastroparesis treatments may include:

• Medicines (e.g., metoclopramide, which helps empty your stomach)
• Surgery to create an opening between your stomach and small intestine

5. Foreign Body Ingestion

Children accidentally swallow foreign objects more commonly than adults. Still, it's easy to mistakenly consume small fish bones from a salmon dinner or a wire barbecue brush bristle that gets stuck to the grill and cooked into a hamburger. 

Also, an uncommon condition called pica can cause people to swallow non-food items intentionally. Pica most commonly affects children and may result from an underlying mental health condition.

Foreign objects usually pass through your digestive system without any damage. In some cases, a foreign body can cause a blockage in your stomach or small intestine. As a result, you may develop abdominal pain, bloating, and nausea.

You may need an endoscopy or X-rays if you develop symptoms. Those tests allow a healthcare provider to see the inside of your digestive system and view the foreign object. Rarely do people require surgery to remove foreign objects.

People with pica may require behavioral therapy and medicines for mental health conditions.

6. Heart Attack

A heart attack occurs if something suddenly blocks blood flow to your heart. Your blood carries oxygen. Your heart muscles weaken and begin to die without oxygen.

The most common signs and symptoms of a heart attack include:

• Chest pain
• Shortness of breath
• Upper body discomfort

Sometimes, women have different heart attack symptoms than men. Those symptoms may include nausea, unexplained tiredness, and vomiting.

Heart attacks are an emergency. Seek medical attention immediately if you or someone near you has heart attack symptoms. 

Treatment may include medicines and surgery to widen your coronary arteries through which blood flows to your heart. A healthcare provider will likely advise cardiac rehabilitation after a heart attack.

Cardiac rehabilitation teaches you how lifestyle changes, such as healthy eating, exercise, and weight loss, may prevent heart problems.

7. Hormonal Reasons

The glands in your body create and secrete hormones responsible for growth, metabolism, sexual function, and mood. You may have nausea if something disrupts the function of your glands. 

Addison's Disease

Addison’s disease is a hormonal disorder in which your adrenal glands do not make enough hormones. Those hormones, such as cortisol, aid your body’s stress response, control your blood pressure, and maintain your salt and water balance.

Common symptoms of Addison’s disease include:

• A loss of appetite
• Abdominal pain
• Fatigue
• Weak muscles
• Weight loss

Sometimes, those symptoms made lead to nausea and vomiting.

People with Addison’s disease must take medicine to regulate their hormone levels. Addison’s disease may be fatal if untreated. Carrying an emergency ID that lists your medicines and dosage is essential.

Diabetic Ketoacidosis

Diabetic ketoacidosis (DKA), a complication of type 1 diabetes, occurs if your pancreas does not produce enough insulin, a hormone. Your cells burn fat for fuel, causing ketones to build up in your blood. High ketone levels cause the blood to become acidic.

In a study published in 2020, researchers found that, out of 71 people with DKA, nearly 58% had nausea. People with DKA may develop vomiting if their blood becomes too acidic.

Other symptoms of DKA include:

• Breath that smells fruity
• Decreased alertness
• Dehydration
• Dry skin and mouth
• Extreme thirst
• Flushed face
• Frequently urinating
• Headaches
• Rapid breathing
• Stiff muscles that may ache

Insulin helps control blood sugar and reverse DKA. You may need to replace lost bodily chemicals and fluids if you are frequently urinating, vomiting, or not eating.

8. Low Blood Sugar

Hypoglycemia, or low blood sugar, happens when your body's blood glucose (sugar) level drops below a certain level. People with diabetes who take insulin or other medicines may develop low blood sugar.

Sometimes, being hungry indicates that your blood sugar is slightly low. Hunger and low blood sugar may lead to nausea in some people.

People with low blood sugar may develop other symptoms like:

• Blurry vision
• Chills
• Feeling dizzy or lightheaded
• Headaches
• Irritability
• Pale skin
• Rapid heart rate
• Shakiness
• Sweating
• Weakness

You can manage your blood sugar level by eating a snack, drinking fruit juice, or taking a glucose tablet. Experts advise that people with diabetes continuously monitor their blood sugar levels and adjust their insulin dose as necessary.

9. Medicines and Supplements

Certain over-the-counter (OTC) and prescription medicines and supplements may irritate your stomach, leading to nausea.

Pain Relievers

Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and naproxen may cause nausea. NSAIDs may increase the risk of bleeding and erosion of the stomach lining.

Taking NSAIDs with food or a glass of milk helps avoid nausea.

Prescription Medicines

Nausea is a common side effect of several prescription medicines, such as:

• Antibiotics
• Antidepressants
• Chemotherapy drugs that treat cancer
• Oral bisphosphonates that treat osteoporosis, a disease that causes weak bones
• Some blood pressure drugs

Talk to a healthcare provider if you take a medicine that causes nausea.

Supplements

Some mineral and vitamin supplements may cause nausea.

For example, vitamin C supplements may upset your stomach. Water moves from your intestines moves to the unabsorbed vitamin C. As a result, you may have abdominal cramps, diarrhea, and nausea.

Iron supplements may cause nausea. Experts advise taking iron supplements on an empty stomach, but you may need a small snack to prevent nausea. Do not consume caffeine, high-fiber foods, or milk with iron supplements. A healthcare provider may suggest lowering your dose if nausea persists.

10. Motion Sickness

Some people get motion sickness when traveling by airplanes, boats, cars, and trains. Motion sickness happens if your body gets mixed signals about whether you are moving. 

For example, you may develop motion sickness if you are focused on a book or your phone while traveling. In that case, your inner ears detect that you are moving, but your eyes do not. As a result, you may have nausea or vomiting.

Try sitting in the front seat of a car, at the front of an airplane or train, or on the upper deck of a boat to prevent motion sickness. Looking out the window while moving may help, too. 

11. Passing Out

Syncope, or passing out, is an uneasy feeling that leads to a brief loss of consciousness. Symptoms occur if a trigger, like extreme heat, causes a drop in blood pressure.

You may feel lightheaded and nauseous before passing out. Other symptoms include feeling clammy or cold and having white or black vision.

Check that a person is breathing if they faint. Keep them lying down for at least 10 minutes after they wake up.

How To Relieve Nausea 

Being nauseous may feel uncomfortable. If you have one of the above conditions, like heart disease or diabetic ketoacidosis, you should see a healthcare provider to treat the condition itself. However, here are some things you can do to help relieve nausea:

• Get rid of a bad taste in your mouth by sucking on hard candies or rinsing. Mix one teaspoon of baking soda and ¾ teaspoon of salt into four cups of warm water. 
• Distract yourself from nausea by watching a movie or TV show.
• Sip slowly on flat soda or fruit juice. Sports drinks help replenish lost fluids and electrolytes if you vomit.
• Sit outside to get fresh air.
• Sit quietly. Moving too much may worsen nausea.
• Stay hydrated. Drink plenty of water, about eight to 10 cups daily.

In contrast, you may want to avoid certain foods if you are nauseous or vomiting, including:

• Alcohol
• Caffeine
• Carbonated drinks
• Dairy products
• Greasy, processed foods with a lot of salt (e.g., canned foods, chips, donuts, fast-food burgers, fried foods, pastries, sausage, white bread)
• Foods with strong smells
• Spicy foods

How To Prevent Nausea 

You can take steps to prevent nausea if you are pregnant or prone to being nauseous in certain situations, such as traveling.

Try some of the following to prevent nausea:

• Avoid eating three big meals. Instead, eat six to eight small meals spread evenly throughout the day.
• Avoid lying down after you eat. 
• Eat crackers before getting out of bed if you are pregnant and have morning sickness.
• Opt for bland foods (e.g., baked chicken and fish, crackers, English muffins, noodles, potatoes, rice, and toast).
• If you get motion sickness, sit in a front seat of a car or bus, and choose the window seat on airplanes or trains. 
• Stay hydrated by eating foods with water in them (e.g., clear soups, Jell-O, and popsicles).
• Take your meals in quiet areas that do not have odors that make you nauseous. 
• Try sipping on a ginger-flavored drink or sucking on ginger candies. Some evidence suggests that ginger may prevent nausea.

A healthcare provider may prescribe anti-nausea medicine if you frequently have nausea. Over-the-counter (OTC) medicines that may prevent motion sickness include Benadryl (diphenhydramine), Dramamine (dimenhydrinate), and scopolamine.

Allow 30–60 minutes for those medicines to work. Talk to a healthcare provider if you vomit after taking anti-nausea medicine.

When To Reach Out to a Healthcare Provider

Nausea is common and generally not serious. Typically, you can treat nausea and vomiting at home.

Talk to a healthcare provider if you notice signs and symptoms like:

• Abdominal pain
• Blood in vomit
• Dehydration (i.e., dark urine, dry mouth, and infrequently urinating)
• Fever
• Nausea lasts longer than 48 hours
• Not urinating for more than eight hours
• Severe headache
• Stiff neck
• Unable to keep food or liquid down
• Vomit more than three times in 24 hours
• Weakness

Consult a healthcare provider right away if you think poisoning has caused your nausea or vomiting.

A Quick Review

A stomach bug and pregnancy are the most common causes of nausea. Still, several other reasons, like anxiety, GERD, pain relievers, and motion sickness, may cause nausea.

You may alleviate and prevent nausea by eating more frequent, small meals and staying hydrated. Consult a healthcare provider if your nausea does not subside within 48 hours.