Cyclic Vomiting 

Syndrome 

National Digestive Diseases Information Clearinghouse 

U.S. Department 

of Health and 

Human Services 

NATIONAL 

INSTITUTES 

OF HEALTH 

What is cyclic vomiting 

syndrome (CVS)? 

CVS is characterized by episodes or cycles 

of severe nausea and vomiting that last for 

hours, or even days, that alternate with 

intervals with no symptoms. Although originally thought to be a pediatric disease, CVS 

occurs in all age groups. Medical researchers believe CVS and migraine headaches are 

related (see “CVS and Migraine” on page 2). 

Each episode of CVS is similar to previous 

ones, meaning the episodes tend to start at 

the same time of day, last the same length of 

time, and occur with the same symptoms and 

level of intensity. Although CVS can begin 

at any age, in children it starts most often 

between the ages of 3 and 7. 

Episodes can be so severe that a person has 

to stay in bed for days, unable to go to school 

or work. The exact number of people with 

CVS is unknown, but medical researchers 

believe more people may have the disorder 

than commonly thought. Because other 

more common diseases and disorders also 

cause cycles of vomiting, many people with 

CVS are initially misdiagnosed until other 

disorders can be ruled out. CVS can be 

disruptive and frightening not just to people 

who have it but to family members as well. 

The Four Phases of CVS 

CVS has four phases: 

•	 Symptom-free interval phase. This 

phase is the period between episodes 

when no symptoms are present. 

•	 Prodrome phase. This phase signals 

that an episode of nausea and vomiting is about to begin. Often marked 

by nausea—with or without abdominal 

pain—this phase can last from just a few 

minutes to several hours. Sometimes, 

taking medicine early in the phase can 

stop an episode in progress. However, 

sometimes there is no warning; a person 

may simply wake up in the morning and 

begin vomiting. 

•	 Vomiting phase. This phase consists 

of nausea and vomiting; an inability to 

eat, drink, or take medicines without 

vomiting; paleness; drowsiness; and 

exhaustion. 

•	 Recovery phase. This phase begins 


when the nausea and vomiting stop. 


Healthy color, appetite, and energy 


return.
 
 

What triggers CVS? 

Many people can identify a specific condition 

or event that triggered an episode, such as 

an infection. Common triggers in children 

include emotional stress and excitement. 

Anxiety and panic attacks are more common triggers in adults. Colds, allergies, sinus 

problems, and the flu can also set off episodes in some people. 

Other reported triggers include eating certain foods such as chocolate or cheese, eating 

too much, or eating just before going to bed. 

Hot weather, physical exhaustion, menstruation, and motion sickness can also trigger 

episodes. 

What are the symptoms 

of CVS? 

A person who experiences the following 

symptoms for at least 3 months—with first 

onset at least 6 months prior—may have 

CVS: 

•	 vomiting episodes that start with severe 

vomiting—several times per hour—and 

last less than 1 week 

•	 three or more separate episodes of vomiting in the past year 

•	 absence of nausea or vomiting between 

episodes 

A person with CVS may experience abdominal pain, diarrhea, fever, dizziness, and 

sensitivity to light during vomiting episodes. 

Continued vomiting may cause severe 

dehydration that can be life threatening. 

Symptoms of dehydration include thirst, 

decreased urination, paleness, exhaustion, 

and listlessness. A person with any symptoms of dehydration should see a health care 

provider immediately. 

How is CVS diagnosed? 

CVS is hard to diagnose because no tests— 

such as a blood test or x ray—can establish 

a diagnosis of CVS. A doctor must look at 

symptoms and medical history to rule out 

other common diseases or disorders that 

can cause nausea and vomiting. Making a 

diagnosis takes time because the doctor also 

needs to identify a pattern or cycle to the 

vomiting. 

CVS and Migraine 

The relationship between migraine 

and CVS is still unclear, but medical 

researchers believe the two are related. 

•	 Migraine headaches, which cause 

severe head pain; abdominal 

migraines, which cause stomach 

pain; and CVS are all marked by 

severe symptoms that start and 

end quickly and are followed by 

intervals without pain or other 

symptoms. 

•	 Many of the situations that trigger 

CVS also trigger migraines, including stress and excitement. 

•	 Research has shown that many children with CVS either have a family 

history of migraine or develop 

migraines as they grow older. 

Because of the similarities between 

migraine and CVS, doctors treat some 

people with severe CVS with drugs that 

are also used for migraine headaches. 

The drugs are designed to prevent 

episodes, reduce frequency, and lessen 

severity. 

2 Cyclic Vomiting Syndrome 
 

How is CVS treated? 

Treatment varies, but people with CVS generally improve after learning to control their 

symptoms. People with CVS are advised to 

get plenty of rest and sleep and to take medications that prevent a vomiting episode, stop 

one in progress, speed up recovery, or relieve 

associated symptoms. 

Once a vomiting episode begins, treatment 

usually requires the person to stay in bed and 

sleep in a dark, quiet room. Severe nausea 

and vomiting may require hospitalization and 

intravenous fluids to prevent dehydration. 

Sedatives may help if the nausea continues. 

Sometimes, during the prodrome phase, it is 

possible to stop an episode from happening. 

For example, people with nausea or abdominal pain before an episode can ask their 

doctor about taking ondansetron (Zofran) or 

lorazepam (Ativan) for nausea or ibuprofen 

(Advil, Motrin) for pain. Other medications 

that may be helpful are ranitidine (Zantac) 

or omeprazole (Prilosec), which help calm 

the stomach by lowering the amount of acid 

it makes. 

During the recovery phase, drinking water 

and replacing lost electrolytes are important. 

Electrolytes are salts the body needs to function and stay healthy. Symptoms during the 

recovery phase can vary. Some people find 

their appetite returns to normal immediately, 

while others need to begin by drinking clear 

liquids and then move slowly to solid food. 

People whose episodes are frequent and 

long-lasting may be treated during the 

symptom-free intervals in an effort to prevent or ease future episodes. Medications 

that help people with migraine headaches, 

such as propranolol (Inderal), cyproheptadine (Periactin), and amitriptyline (Elavil), 

are sometimes used during this phase, but 

they do not work for everyone. Taking the 

medicine daily for 1 to 2 months may be 

necessary before one can tell if it helps. 

The symptom-free interval phase is a good 

time to eliminate anything known to trigger 

an episode. For example, if episodes are 

brought on by stress or excitement, a 

symptom-free interval phase is the time to 

find ways to reduce stress and stay calm. If 

sinus problems or allergies cause episodes, 

those conditions should be treated. 

During an episode, anti-migraine drugs such 

as sumatriptan (Imitrex) may be prescribed 

to stop symptoms of migraine headache. 

However, these agents have not been studied 

for use in children. 

3 Cyclic Vomiting Syndrome 
 

What are the complications 

of CVS? 

The severe vomiting that defines CVS is a 

risk factor for several complications: 

•	 Dehydration. Vomiting causes the body 

to lose water quickly. Dehydration 

can be severe and should be treated 

immediately. 

•	 Electrolyte imbalance. Vomiting causes 

the body to lose important salts it needs 

to keep working properly. 

•	 Peptic esophagitis. The esophagus— 

the tube that connects the mouth to 

the stomach—becomes injured from 

stomach acid moving through it while 

vomiting. 

•	 Hematemesis. The esophagus becomes 

irritated and bleeds, so blood mixes with 

vomit. 

•	 Mallory-Weiss tear. The lower end of 

the esophagus may tear open or the 

stomach may bruise from vomiting or 

retching. 

•	 Tooth decay. The acid in vomit can hurt 

teeth by corroding tooth enamel. 

Points to Remember 

•	 People with CVS have severe nausea 

and vomiting that come in cycles. 

•	 CVS occurs in all age groups. 

•	 Medical researchers believe CVS and 

migraine headaches are related. 

•	 CVS has four phases: symptom-free 

interval phase, prodrome phase, vomiting phase, and recovery phase. 

•	 Many people can identify a condition or 

event that triggers an episode of nausea 

and vomiting. Infections and emotional 

stress are two common triggers. 

•	 The main symptoms of CVS are episodes of nausea and vomiting that come 

and go. Vomiting can lead to severe 

dehydration that can be life threatening. 

•	 Symptoms of dehydration include thirst, 

decreased urination, paleness, exhaustion, and listlessness. A person with any 

symptoms of dehydration should see a 

health care provider immediately. 

•	 The only way a doctor can diagnose 

CVS is by looking at symptoms and 

medical history to rule out any other 

possible causes for the nausea and vomiting. Then the doctor must identify a 

pattern or cycle to the symptoms. 

•	 Treatment varies by person, but people 

with CVS generally improve after learning to control their symptoms. They 

may also be given medications that 

prevent a vomiting episode, stop one in 

progress, speed up recovery, or relieve 

associated symptoms. 

•	 Complications include dehydration, 

which can be severe; electrolyte imbalance; peptic esophagitis; hematemesis; 

Mallory-Weiss tear; and tooth decay. 

4 Cyclic Vomiting Syndrome 
 

 

 

 

 

 

 

 

 

 

 

Hope through Research 

The National Institute of Diabetes and 

Digestive and Kidney Diseases’ Division 

of Digestive Diseases and Nutrition supports basic and clinical research into functional gastrointestinal disorders, including 

cyclic vomiting syndrome. More research is 

needed in the areas of diagnosis and treatment of this condition. 

Participants in clinical trials can play a more 

active role in their own health care, gain 

access to new research treatments before 

they are widely available, and help others by 

contributing to medical research. For information about current studies, visit 

www.ClinicalTrials.gov. 

For More Information 

Cyclic Vomiting Syndrome Association 

2819 West Highland Boulevard 

Milwaukee, WI 53208 

Phone: 414–342–7880 

Fax: 414–342–8980 

Email: cvsa@cvsaonline.org 

Internet: www.cvsaonline.org 

National Organization for Rare Disorders 

55 Kenosia Avenue 

P.O. Box 1968 

Danbury, CT 06813–1968 

Phone: 1–800–999–6673 or 203–744–0100 

Fax: 203–798–2291 

Email: orphan@rarediseases.org 

Internet: www.rarediseases.org 

You may also find additional information about this 


topic by
 

• searching the NIDDK Reference Collection at 

www.catalog.niddk.nih.gov/resources

• visiting MedlinePlus at www.medlineplus.gov

This publication may contain information about medications. When prepared, this publication included 

the most current information available. For updates 

or for questions about any medications, contact 

the U.S. Food and Drug Administration toll-free at 

1–888–INFO–FDA (463–6332) or visit www.fda.gov. 

Consult your doctor for more information. 

The U.S. Government does not endorse or favor any 

specific commercial product or company. Trade, 

proprietary, or company names appearing in this 

document are used only because they are considered 

necessary in the context of the information provided. 

If a product is not mentioned, the omission does not 

mean or imply that the product is unsatisfactory. 

5 Cyclic Vomiting Syndrome 
 

 

 

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Internet: www.digestive.niddk.nih.gov
 

The National Digestive Diseases Information 

Clearinghouse (NDDIC) is a service of the 

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and Kidney Diseases (NIDDK). The NIDDK 

is part of the National Institutes of Health of 

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This publication is not copyrighted. The Clearinghouse encourages users of this fact sheet to duplicate 

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This fact sheet is also available at 

www.digestive.niddk.nih.gov.

U.S. DEPARTMENT OF HEALTH 

AND HUMAN SERVICES 

National Institutes of Health 

NIH Publication No. 09–4548 

December 2008