The diagnosis of CVS can be difficult because vomiting may be caused by a large number of other disorders that are more common. CVS is usually a diagnosis by exclusion of all other causes. At present there are no diagnostic methods (e.g. no blood or urine tests) that can be used to diagnose the disorder. A diagnosis, or, more correctly, a classification of CVS may take several years to achieve. Many sufferers will undergo numerous tests and sometimes misdiagnoses before their condition is recognised.

Formal criteria for diagnosis are shown below, but these probably omit some very common signs. In some people the intense nausea is the predominant symptom. As will be seen there is no single agreed set of criteria, which serves to highlight the problems in obtaining a diagnosis.

In CVS, the pattern of vomiting is such that at the peak this can be 5-6 times per hour. This is different from vomiting induced by most other causes. Onset of vomiting is most often between 2 am and 8 am. Again, this is unusual in other forms of vomiting.

In 1994, the CVSA UK and USA (with support from Glaxo Wellcome) sponsored a symposium on CVS held in London, UK. During the meeting, a series of criteria were agreed for the formal diagnosis of CVS. In many ways this was a huge step forward in the recognition of CVS and its wider acceptance as a serious health issue. Essential criteria are a requirement for diagnosis. Supportive criteria may strengthen the diagnosis, but not all of the criteria may be apparent in any one individual. Associated signs are features that are more difficult to quantitate but may be associated with CVS. The proceedings of this symposium were published (see References).

Essential Criteria

  • Recurrent, severe, discrete episodes of vomiting
  • Various intervals of normal health between episodes
  • Duration of vomiting episodes from hours to days
  • No apparent cause of vomiting

Supportive Criteria


Stereotypical: each episode similar within individuals as to time of onset, intensity, duration, frequency, and associated symptoms and signs.
Associated Symptoms

  • Nausea
  • Abdominal Pain
  • Headache
  • Motion Sickness
  • Photophobia

Associated Signs

  • Fever
  • Pallor
  • Diarrhoea
  • Dehydration
  • Excess Salivation
  • Social Withdrawal
Rome VI Criteria

The Rome criteria is a system developed to classify the functional gastrointestinal disorders (FGIDs), disorders of the digestive system in which symptoms cannot be explained by the presence of structural or tissue abnormality, based on clinical symptoms. Some examples of FGIDs include irritable bowel syndrome, functional dyspepsia, functional constipation, and functional heartburn as well as CVS. About Rome.

H1a. Diagnostic Criteria for Cyclic Vomiting Syndrome must include all of the following:

  1. The occurrence of 2 or more periods of intense, unremitting nausea and paroxysmal vomiting, lasting hours to days within a 6-month period.
  2. Episodes are stereotypical in each patient
  3. Episodes are separated by weeks to months with return to baseline health between episodes.
  4. After appropriate medical evaluation, the symptoms cannot be attributed to another condition.

Dr Douglas Drossman, is  professor emeritus of medicine and psychiatry at the University of North Carolina School of Medicine. He is founder, President Emeritus and Chief of Operations of the Rome Foundation. He gives a brief overview of the symptoms and treatment of CVS.

From the Rome Foundation
North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NAPGH)

At least 5 attacks in any interval, or a minimum of 3 attacks during a six month period. Episodic attacks of intense nausea and vomiting lasting 1h–10 days and occurring at least one week apart. Stereotypical pattern and symptoms in the individual patient. Vomiting during attacks occurs at least 4 times/h for at least 1 hr. Return to baseline health between episodes. Not attributed to another disorder.

Li et al, J Ped Gastroenterol Nutr 47 379-393 2008

The International Headache Society

International Classification of Headache Disorders (ICHD) beta III 2013

Look at diagnostic criteria in section here.