Emetophobia is the irrational fear of vomiting, being around others who are vomiting, and/or the vomit itself.
In worst case scenarios, people with the phobia tend to avoid eating out, socializing and going to parties. They may hardly eat at all and that's why many are often diagnosed as anorexic, but not bulimic as this illness involves the induction of vomiting. Emetophobics will go to extraordinary lengths to avoid becoming violently sick ("vomit continence," Nicolette Heaton-Harris & Linda Dean (2007), Emetophobia, ISBN 1843105365, p. 20), or seeing someone else becoming sick.