What is the best medicine for right abdominal pain during menstruation?

Pain in the right abdomen during menstruation is commonly associated with dysmenorrhoea.
If the cause has been clearly identified as dysmenorrhoea, non-steroidal anti-inflammatory drugs (e.g. ibuprofen) can be taken under medical supervision to improve symptoms. If necessary, patients can also take oral contraceptives to inhibit endometrial hyperplasia and thus avoid dysmenorrhoea.