Background: Vaccines have come a long way. They have been an important aspect of controlling and eradicating various life-threatening diseases. Vaccination is being widely used for Influenza which is one of the most common conditions affecting a large population and affects day to day activity. A vaccine being a double-edged sword, it presents various side effects as a whole and on oral cavity like ulcers, bleeding gums, white spots, sores in the oral cavity, lips, along with halitosis, etc.
 Objective: This prospective study was aimed to assess and understand the bad impact on by influenza vaccine on the oral cavity as well as to establish if any correlation exists between the flu vaccine and adverse oral symptoms.
 Methods: A total of 268 subjects studying at Government Medical College, were randomly screened for the study. Out of which only 32 received the vaccine for influenza in the past 6 months. All the subjects were given a multiple-choice questionnaire consisting of 12 short response questions related to general and oral side effects post-vaccination. The data collected was evaluated and assessed.
 Results: Study subjects that took the influenza vaccine within a period of the past 6 months, only ten patients suffered by side effects in which 6 suffered from flu-like symptoms and only 4 suffered orally-related symptoms simultaneously. Three manifestations that were found related to the oral cavity were white patches in the oral cavity, swelling of the lips, and atypical oral ulcers, soreness, swelling, redness, and pain in the upper arm. Other symptoms encountered in responders were fever, weakness, headache, and dizziness. The results of the present study indicated that 30% (n=3) of participants reported moderate pain (level 2). The remaining 70% reported levels 1, 3, and 5 pain with 30% reported level 1, 20% level 3 pain, and 20% level 5 pain respectively of Likert’s Pain Scale. Only 2 subjects (20%) required medical treatment for experienced symptoms. The severely unbearable pain of level 5 was reported by 2 subjects.
 Conclusions: No substantial relationship is observed between receiving the flu vaccine and oral symptoms. The most common symptom reported by survey participants were soreness, redness, and swelling in the upper arm with associated pain. All these systems are part of body immune defence to foreign vaccine particles and are cured naturally with immunity.
 Keywords: Flu, Immune Reaction, Influenza, Oral Cavity, Vaccination.