Vomiting is a reflex act of expelling the contents of the stomach and sometimes the intestines that can be voluntarily or involuntarily. Vomiting is the body’s way of getting rid of harmful substances from the stomach, or it can be a reaction to something that has irritated the intestines.
Vomiting can be classified as acute (short-lived isolated episode) or chronic (recurring). One of the most common causes of vomiting in adults is gastroenteritis, an infection of the intestines usually caused by bacteria or a virus, which typically resolves within a few days. Vomiting occasionally can be a sign of a more serious condition, such as appendicitis. Vomiting often leads to dehydration, which is more common in children and infants. In some cases, dehydration can be life-threatening.
Vomiting is controlled by two different centers in the brain – the vomiting center and the chemoreceptor trigger zone – both located in the medulla oblongata.
The vomiting center initiates and controls the act of vomiting, which involves a series of contractions of the smooth muscles lining the digestive tract. These contractions start in the small intestine and progress successively through the stomach and esophagus until the contents of the stomach are expelled through the mouth. The vomiting center directly responds to stimuli from various parts of the body that may be under stress or illness. In contrast, the chemoreceptor trigger zone is stimulated by many toxins and medications.
Activation of this brain region stimulates the vomiting center, which triggers vomiting in an attempt to rid the body of toxins. In severe cases, vomiting can lead to dehydration, malnutrition, or rupture of the esophageal wall. Treatment is aimed at addressing the underlying cause of vomiting. It is important to drink plenty of clear fluids to prevent further dehydration.
Phases of vomiting
Nausea: an unpleasant sensation of the urge to vomit, often accompanied by cold sweats, paleness, increased salivation, loss of gastric tone, contraction of the duodenum, and reflux of intestinal contents into the stomach. Nausea usually precedes vomiting but can also occur alone.
The urge to vomit: a strong involuntary attempt at vomiting and is usually accompanied by nausea. The abdominal muscles, chest muscles and diaphragm contract without any expulsion of gastric contents.
Vomiting: forceful expulsion of gastrointestinal contents through the mouth. Scientists believe that this reflex act has evolved as a defensive mechanism to help the body rid itself of harmful substances rather than retaining and absorbing them in the intestines. Contrary to popular belief, the stomach itself does not actively expel its contents during vomiting. The stomach, esophagus, and their sphincters are actually relaxed during vomiting. Most of the force expelling the contents comes from the contraction of the diaphragm, which is the main respiratory muscle, and the abdominal muscles, which are involved in active exhalation.
The difference between nausea and vomiting
Nausea is discomfort in the stomach that is often accompanied by the urge to vomit, but it does not always lead to vomiting. Some triggers that can lead to vomiting may originate from the stomach and intestines (infection, injury, and food irritation), inner ear (dizziness and motion sickness), and the brain (head injuries, brain infections, tumors, and migraines).
The color of vomit can indicate possible causes
Some people only get cramps, a strong urge to vomit, but without any content. However, most people expel gastric contents, and the color of the vomit can provide clues to the underlying cause. Blood in vomit usually indicates a cut or scratch in the esophagus or stomach.
Gastric content sometimes resembles coffee grounds, which occurs when stomach acid and blood coagulate. It can be a sign of an ulcer, gastroesophageal reflux disease (GERD), stomach or liver cancer, or other abdominal conditions. Vomiting yellow or greenish contents indicates the presence of bile, which typically happens after a meal. Orange vomit usually suggests food poisoning.
Who can vomit?
Vomiting can occur in anyone, including children and adults, regardless of age, gender, or health condition.
People undergoing cancer treatment, such as radiation therapy or chemotherapy, have an increased risk of experiencing nausea and vomiting (a condition known as morning sickness). Pregnant women in the first trimester may also experience nausea and vomiting. It is estimated that 50 to 90 percent of pregnant women experience nausea, and 25 to 55 percent experience vomiting.
Cyclic vomiting syndrome
Cyclic vomiting syndrome is a rare disorder characterized by severe nausea and vomiting that can occur at any age. People with this condition experience a cyclic pattern of intense vomiting that lasts for several hours to several days, followed by a symptom-free period. The exact cause of cyclic vomiting syndrome is unknown, but researchers have identified a link between this condition and migraines.
Symptoms of vomiting
- Excessive salivation
- Sweating
- Increased heart rate
- Pallor
- Nausea
- Urge to vomit
Causes of vomiting
The causes of vomiting vary depending on age. In adults, vomiting is usually caused by viral infections, food poisoning, motion sickness, and illnesses accompanied by high fever. In children, it is common for them to vomit due to viral infections, food poisoning, motion sickness, overeating or force-feeding, coughing, and illnesses where the child has a high fever. Although rare, intestinal obstruction can cause vomiting, most commonly in early childhood.
General causes of vomiting
Motion sickness and other motion-related illnesses: People who experience nausea in cars, boats (motion sickness), airplanes, or during amusement park rides suffer from motion-related illnesses. This condition can cause cold sweats, dizziness, a feeling of unsteadiness, nausea, and vomiting. Women and children are more prone to motion sickness, but it can affect anyone.
Early pregnancy: Besides fatigue and absence of menstruation, nausea accompanied by vomiting (often referred to as “morning sickness,” although it can occur at any time) is a common symptom of early pregnancy.
Intense pain: Pain, which can result from various conditions and illnesses, can interfere with daily activities. Causes of pain can include overeating, intestinal infections, stress and anxiety, and chronic gastrointestinal disorders. Stomach pain and nausea are usually short-lived and go away on their own. However, intense pain can be a symptom of other conditions, so medical attention is necessary in any case.
Exposure to chemical toxins: Along with headaches and irritation of the nasal, oral, and eye mucosa, symptoms of poisoning can include nausea and vomiting.
Emotional stress (fear): When a person is under stress, the body releases a surge of hormones to prepare for facing or escaping from perceived threats. These hormones trigger the “fight or flight” response. Being in this survival mode affects all bodily systems, including the digestive system. Anxiety can manifest through a range of gastrointestinal (GI) symptoms, including stress-induced nausea, abdominal pain, changes in bowel habits and movements, and even stress-induced vomiting.
Gallbladder disease: The gallbladder’s task is to store digestive juice called bile, which it releases into the small intestine when needed to break down fats. However, if the pathway to the small intestine is blocked, the bile remains trapped, which can irritate the gallbladder and lead to cholecystitis. Nausea and vomiting are common symptoms, often occurring after a large and fatty meal.
Food poisoning: An illness caused by consuming contaminated food and beverages. The causes can be microorganisms or other harmful substances in the food or drink. The main symptoms of food poisoning are nausea, vomiting, and diarrhea.
Poor digestion: A sense of discomfort or burning in the upper abdomen. It may be accompanied by heartburn, burping, bloating, and often nausea and vomiting.
Various viruses: Rotavirus, adenovirus, and astrovirus are the most common causes of infections in newborns and young children but can also infect adults. Viruses can cause viral gastroenteritis at any time of the year.
Specific odors: Hyperosmia, oversensitivity to smells, can be extremely unpleasant. A person may feel nauseated or queasiness, have an urge to vomit, and certain odors can even trigger migraines or allergies.
Serious causes of vomiting
Vomiting is usually harmless but can be a sign of a more serious illness. Some examples of serious conditions that can cause nausea or vomiting are:
Concussion: It is estimated that 78% of people who have experienced a traumatic brain injury, such as a concussion, have balance issues, and most experience nausea and vomiting. Nausea and vomiting immediately after a head injury are clear signs of a concussion, and immediate medical attention should be sought.
Encephalitis: Acute inflammation of the brain caused by infection or an autoimmune response. Inflammation leads to brain swelling, which can result in headaches, neck stiffness, sensitivity to light, mental confusion, and seizures. Severe cases of encephalitis can cause high fever, nausea, and vomiting. In some cases, encephalitis can be life-threatening. Prompt diagnosis and treatment are important as it is difficult to predict how encephalitis will affect each individual.
Meningitis: Meningitis is an infection and inflammation of the fluid and membranes surrounding the brain and spinal cord. Early symptoms of meningitis can resemble the flu. Symptoms can develop over a few hours or several days and may include sudden high fever, neck stiffness, severe headache, nausea or vomiting, confusion or difficulty concentrating, and seizures. If meningitis symptoms are present, immediate medical attention is necessary. Early treatment of meningitis can prevent serious complications.
Intestinal obstruction (blockage): Intestinal obstruction is a condition in which food and fluids cannot pass through the intestines. Intestinal obstructions typically cause cramps, abdominal pain, vomiting, and an inability to empty the intestines. Intestinal obstruction is a life-threatening condition and requires immediate hospitalization to prevent serious complications. Treatment often involves surgery.
Appendicitis: Severe pain, usually around the belly button or in the lower right abdomen (pain may initially come and go and then become steady and intense), loss of appetite, nausea, and vomiting are clear signs of appendicitis. Appendicitis occurs when the appendix becomes inflamed and filled with contents and bacteria. If appendicitis is left untreated, the appendix can swell and eventually burst, releasing infected contents into the abdomen, and causing a potentially life-threatening infection.
Headaches and migraines: Migraine is a common type of headache. It can occur with symptoms such as nausea, vomiting, or sensitivity to light. Most people feel a pulsating pain on one side of the head during a migraine. Nausea and vomiting along with severe headaches are reasons to seek medical attention. If a person experiences the most intense headache they have ever had, loses vision or consciousness, or uncontrollably vomits, they should seek immediate medical help.
Brain tumors: When a tumor grows within the confined space of the skull, it can compress brain tissue or block the flow of fluid within the brain. In both cases, it can lead to increased pressure inside the skull, known as increased intracranial pressure. The consequences of this pressure include nausea, vomiting, and headaches.
Controlling or alleviating vomiting
There are several ways you can control nausea and prevent vomiting yourself:
- Drink clear or ice-cold fluids.
- Drink slowly.
- Eat light, unsalted foods (such as crackers or plain bread). Avoid fried, fatty or sweet foods. Eat slowly and eat smaller, more frequent meals. Do not mix hot and cold food. Avoid physical activity immediately after eating.
- Avoid brushing your teeth after eating.
- Avoid odors that trigger your nausea.
If these techniques do not alleviate your nausea, you should speak to a doctor.
The treatment for vomiting
- Drink gradually increasing amounts of clear fluids.
- Avoid solid foods until the vomiting episode subsides.
- Get some rest.
- Temporarily stop taking medications that may irritate your stomach and worsen vomiting.
- If vomiting persists for more than 24 hours, use an oral rehydration solution to prevent and treat dehydration. This solution is also suitable for children.
Medication for vomiting: Drugs that treat nausea and vomiting are called antiemetics and several of them can be purchased at a pharmacy without a prescription. These are:
- bismuth-subcitrate which may help treat some types of nausea and vomiting, such as gastroenteritis (stomach flu). Bismuth subsalicylate works by protecting the stomach lining.