###Human: I am having mouth ulcers after protected sex. Why? ###Assistant: Hello. Do not worry much. I have seen your blood reports (attachment removed to protect patient identity), which states that you are negative for HIV, HCV, syphilis, herpes and other sexually transmitted diseases. As you are explaining, you have a recurrent mouth ulcer and neuropathy like sensation can be explained by mineral, vitamins deficiency, crohns diseases, anemia or any local cause. As u have been tested for all but did not see your complete blood count report and we do not want to miss common cause for that. Kindly follow following instructions. Do CBC, LFT, RFT, AEC, vitamin B12 test. Take tablet Vitamin B complex, crush in water and make mouth gargle 3 to 4 times a day. Tablet Supradyn (multivitamin) twice in a day. Stop smoking, chewing tobacco, hot tea, if you are taking. Use mouth jelly for local applications. Orajel (Benzocaine) ointment for mouth ulcer.