If it persists, you should have cause of concern. Milk of magnesia will not help much. I would recommend simple herbal combos, without side effects and having ' lekhan' properties i.e. it grinds the excretable material stuck inside intestinal walls and can't generally be removed by modern medicine. Once lekhan of such material is successfully done, the digestion, assimilation and other digestive procedures will start taking place in a refreshed mode as if you have cleared the junk in cache memory.