The fear of vomiting, also called emetophobia, does affect a significant section of the population. If you follow any of the following behaviours, particularly more then one then you may have a fear of vomiting.
Avoid spice and unusual cuisines, do not drink, dislike social events and dinner parties, eat in public very little and always sit close to the door, always look at expiration and sell by dates, do not fly or travel by boat, do not use public transportation, avoid anyone that is sick or imagines they are sick, always carry water or mints with you, to name but a handful of behaviours associated with those that have a fear of vomiting.
The fear of vomiting is just like any other type of phobia. It began in childhood and you have never outgrown are resolved that issue. You may have been in a traumatic event or witnessed a traumatic event. As a child you will develop negative emotions to what occurred in the event and you will try to avoid those events to protect yourself. Even when an adult you may revert to acting like a child when vomiting is involved.
This type of fear occurs in two different forms. Some individuals may have a constant fear that can take over their life while others may only experience the fear when vomit or vomiting is present. Many times individuals may not know that they have this fear because they are not exposed top vomiting and then it manifests itself after years without any concern.
A possible type of treatment for this fear is regression hypnotherapy in which you return to that first incident and view it through your adult perspective. You can see the event for its true nature and correct any fear you had associated with vomiting. This type of treatment is effective with even the most severe cases of emetophobia.