What causes amonia smell during period?

Proteins: When you menstruate you slough off the lining of your uterus. The is a large number of proteins in this fluid and they are in cellular material that is decaying. This is where the ammonia smell come from.

Possibily BV: It is possible that you have Bacterial Vaginosis, a vaginal infection caused by a shift in normal vaginal flora to pathogenic bacteria, which release amines, causing a strong fishy odor, worse with sexual intercourse. You will need testing to confirm diagnosis and to obtain prescription medication for treatment.