There could be many reasons for the abdominal pain. The best way is to diagnose the real cause of the pain and then it should be treated accordingly. As a first aid measure take salt equal to one grain of rice and dissolve it in one tea-spoon of water.
اللَّهُ لََا إِلَهَ إِلََّا ھُوَ الْحَيُّ الْقَیُّوم
blow upon this water and let the patient drink this water. The patient should be facing north when this water is taken.