What Causes Nausea for No Reason?

Nausea is a sensation of an urge to vomit.

Nausea is a sensation of an urge to vomit. It may or may not accompany vomiting. Nausea is not a condition in itself but mainly a symptom of underlying medical conditions such as follows:

• Motion sickness
• Migraine headache
• Postural orthostatic hypotension (a decrease in blood pressure on standing up from a sitting or lying position) 
• Autonomic dysfunction (problems with the part of the nervous system responsible for the control of body functions not consciously directed such as breathing, heartbeat, and digestion) 
• Nonulcer dyspepsia (discomfort in the stomach unrelated to an ulcer)
• Peptic ulcer disease
• Gastroesophageal reflux disease (GERD)
• Bowel obstruction (a condition in which the nerves and brain signals prevent the food from passing through the digestive tract even without a physical blockage)
• Gastroparesis (slow stomach emptying or digestion)
• Pancreatic cancer
• Pancreatitis (inflammation of the pancreas)
• Gallbladder disease
• Infections
• Bulimia (eating disorder)
• Appendicitis
• Early stages of pregnancy (during the first trimester)
• Heart attack
• Heart failure
• Cyclic vomiting syndrome (severe attacks of vomiting or nausea)
• Anorexia nervosa (a psychological disorder in which an individual considers themselves as being overweight or controls the shape and size of a specific body part even when they are extremely thin)
• Brain tumor
• Irritable bowel syndrome
• Meningitis (inflammation of the meninges covering the brain and spinal cord)
• Vestibular neuritis (inflammation of the nerves connecting the inner ear to the brain)

Diseases in the following regions may cause nausea:

• Brain or spinal fluid
• Balance centers in the inner ear
• Abdominal or pelvic organs

Moreover, nausea can be associated with causes that aren’t due to underlying diseases, which include:

• Emotional stress (fear)
• An excessive amount of alcohol
• Pill is taken on an empty stomach
• Ingestion of toxins
• Intense pain
• Overeating
• Aversion to strong odors
• Chemotherapy
• Medications such as opioids, cannabis, aspirin, oral contraceptives, and antibiotics

The cause of nausea and vomiting can be determined by its timing:

• Food poisoning, gastritis, ulcer, or bulimia: Appears shortly after a meal
• Salmonella food poisoning: Takes longer to produce symptoms
• Food poisoning due to Clostridium perfringens: Eight hours after a meal

The causes of nausea and vomiting in children may vary from those in adults, and they include the following:

• Viral infection
• Food poisoning
• Milk allergy
• Motion sickness
• Overeating or feeding
• Coughing
• Blocked intestines
• Diseases having high fever as a primary symptom
• Intussusception (a grave condition in which the part of the intestine slips into an adjoining part of the intestine)

What are the symptoms of nausea?

Nausea may occur alone or may be accompanied by certain symptoms. Nausea accompanied by symptoms may indicate an underlying medical condition:

• Nausea with abdominal pain indicates diseases that involve structural alterations (e.g. cholelithiasis).
• Abdominal tenderness with nausea suggests bowel obstruction.
• Vomiting of blood-like material may indicate upper gastrointestinal bleeding.
• Heartburn with nausea signals gastroesophageal reflux disease (GERD).
• Early morning nausea or vomiting is typical of the early stages of pregnancy.
• Headache with nausea indicates migraine.
• Vomitus with sediments indicates an intestinal blockage.
• Nausea with rapid involuntary eye movements signals vestibular neuritis.
• Nausea with tooth enamel erosion, fine hair, and hardening of the skin in the upper portion of palms signals bulimia.

When to call a doctor?

Call the physician immediately if you observe these symptoms:

• Blood in the vomit
• Intense headache or neck stiffness
• Intense abdominal pain
• Confusion
• Lethargy
• Severe abdominal pain
• Rapid breathing or pulse
• Diarrhea along with vomiting
• Severe abdominal pain
• Vomiting with a high fever over 101°F
• Decreased alertness