The feeling that one is about to vomit is called nausea, which often precedes, but does not always lead to, vomiting.

Nausea is an unpleasant, diffuse sensation of unease and discomfort, often perceived as an urge to vomit.

Vomiting can be caused by a wide variety of conditions; it may present as a specific response to ailments like gastritis or poisoning, or as a non-specific sequela of disorders ranging from brain tumors and elevated intracranial pressure to overexposure to ionizing radiation.

These symptoms may include headaches, seizures, problems with vision, vomiting and mental changes.

Vomiting can be caused by a wide variety of conditions; it may present as a specific response to ailments like gastritis or poisoning, or as a non-specific sequela of disorders ranging from brain tumors and elevated intracranial pressure to overexposure to ionizing radiation.

Other possible symptoms include nausea and vomiting, bloating, loss of appetite and heartburn.

Antiemetics are sometimes necessary to suppress nausea and vomiting.

An antiemetic is a drug that is effective against vomiting and nausea.

Receptors on the floor of the fourth ventricle of the brain represent a chemoreceptor trigger zone, known as the area postrema, stimulation of which can lead to vomiting.

The area postrema is a medullary structure in the brain that controls vomiting.

Vomiting is different from regurgitation, although the two terms are often used interchangeably.

It is in most animals a normal and voluntary process unlike the complex vomiting reflex in response to toxins.

Vomiting can be caused by a wide variety of conditions; it may present as a specific response to ailments like gastritis or poisoning, or as a non-specific sequela of disorders ranging from brain tumors and elevated intracranial pressure to overexposure to ionizing radiation.

In general, symptoms and signs that suggest a rise in ICP include headache, vomiting without nausea, ocular palsies, altered level of consciousness, back pain and papilledema.

Receptors on the floor of the fourth ventricle of the brain represent a chemoreceptor trigger zone, known as the area postrema, stimulation of which can lead to vomiting.

The chemoreceptor trigger zone (CTZ) is an area of the medulla oblongata that receives inputs from blood-borne drugs or hormones, and communicates with other structures in the vomiting center to initiate vomiting.

The vagal and enteric nervous system inputs transmit information regarding the state of the gastrointestinal system. Irritation of the GI mucosa by chemotherapy, radiation, distention, or acute infectious gastroenteritis activates the 5-HT 3 receptors of these inputs.

Symptoms may include diarrhea, vomiting, and abdominal pain.

Self-induced vomiting can be a component of an eating disorder, such as bulimia nervosa, and is itself now an eating disorder on its own, purging disorder.

Purging disorder is an eating disorder characterized by recurrent purging (self-induced vomiting, misuse of laxatives, diuretics, or enemas) to control weight or shape in the absence of binge eating episodes.

A less frequent occurrence results from a vomiting of intestinal contents, including bile acids and, which can cause metabolic acidosis.

severe anxiety due to hypoxia, decreased visual acuity, nausea, vomiting, abdominal pain, altered appetite and weight gain, muscle weakness, bone pain, and joint pain.

Repeated or profuse vomiting may cause erosions to the esophagus or small tears in the esophageal mucosa (Mallory–Weiss tear).

This is usually caused by severe vomiting because of alcoholism or bulimia, but can be caused by any conditions which causes violent vomiting and retching such as food poisoning.

Fresh blood in the vomit is termed hematemesis ("blood vomiting").

Hematemesis or haematemesis is the vomiting of blood.

Under normal circumstances the gag reflex and coughing prevent this from occurring; however, these protective reflexes are compromised in persons under the influences of certain substances such as alcohol or anesthesia.

Acute complications include cough syncope (fainting spells due to decreased blood flow to the brain when coughs are prolonged and forceful), insomnia, cough-induced vomiting, rupture of blebs causing spontaneous pneumothorax (although this still remains to be proven), subconjunctival hemorrhage or "red eye", coughing defecation and in women with a prolapsed uterus, cough urination.

The vestibular system, which sends information to the brain via cranial nerve VIII (vestibulocochlear nerve), plays a major role in motion sickness, and is rich in muscarinic receptors and histamine H 1 receptors.

If the cause of the nausea is not resolved, the sufferer will usually vomit, but vomiting may not relieve the feeling of weakness and nausea, which means the person might continue to vomit until the underlying cause of the nausea is resolved.

Altered blood bears resemblance to coffee grounds (as the iron in the blood is oxidized) and, when this matter is identified, the term coffee-ground vomiting is used.

Coffee ground vomitus refers to a particular appearance of vomit.

Combined with the resulting alkaline tide, this leads to hypochloremic metabolic alkalosis (low chloride levels together with high and and increased blood pH) and often hypokalemia (potassium depletion).

Vomiting results in the loss of hydrochloric acid (hydrogen and chloride ions) with the stomach contents. In the hospital setting this can commonly occur from nasogastric suction tubes.

Cholecystitis, pancreatitis, appendicitis, hepatitis

Some people have no symptoms whereas others develop yellow discoloration of the skin and whites of the eyes, poor appetite, vomiting, tiredness, abdominal pain, or diarrhea.

Vomiting is ordinarily preceded by retching.

Retching (also known as dry heaving) is the reverse movement (retroperistalsis) of the stomach and esophagus without vomiting.

Cholecystitis, pancreatitis, appendicitis, hepatitis

Symptoms commonly include right lower abdominal pain, nausea, vomiting, and decreased appetite.

Combined with the resulting alkaline tide, this leads to hypochloremic metabolic alkalosis (low chloride levels together with high and and increased blood pH) and often hypokalemia (potassium depletion).

Rather, heavy urinary losses of K + in the setting of postemetic bicarbonaturia force urinary potassium excretion (see Alkalosis below).

* Hyperemesis, morning sickness

Hyperemesis gravidarum (HG) is a pregnancy complication that is characterized by severe nausea, vomiting, weight loss, and possibly dehydration.

Fecal vomiting is often a consequence of intestinal obstruction or a gastrocolic fistula and is treated as a warning sign of this potentially serious problem (signum mali ominis).

Signs and symptoms include abdominal pain, vomiting, bloating and not passing gas.

Cholecystitis, pancreatitis, appendicitis, hepatitis

Signs and symptoms of pancreatitis include pain in the upper abdomen, nausea and vomiting.

Migraine

Associated symptoms may include nausea, vomiting, and sensitivity to light, sound, or smell.