Hi.. Can understand your concern. As per your complain vomiting after extraction can occur in case if you take the medicines on an empty stomach and the medicines can lead to irritation in the stomach and thus cause vomiting.. It can also occur as the side effect of some medicine prescribed to you by your dentist.. At times if the patient swallows blood during the dental procedure it can also lead to vomiting if blood is swallowed in more quantities as the blood is not digested into the human body leading to vomiting.. You should start eating light food as advised by your doctor as well as drink plenty of water to keep hydrated as there is water loss during vomiting as well as take medicine on time. In case if you do not find any improvement or the vomiting persist it can be most probably due to medicine side effect and you need to consult your dentist for the change of medicine.. Hope your query is solved.. If you find the answer helpful please write a positive review and click on find this answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora.