- The Cyclical Vomiting Syndrome Association, CVSA, is a registered charity run by parents and sufferers in order to provide support, information and research. All medical information presented on these pages has been reviewed by our medical advisors Registered Charity No. 1045723 Web site, promotional material and newsletters prepared using software kindly donated by Adobe Inc. 25/3/02 ...freespace.virgin.net/cvsa.uk