Most laxatives do not have any side effect if prescribed under the supervision of the doctor concerned. But sometimes they can cause cramping, bloating, nausea or diarrhea, gas. The products rich in senna may cause red or yellow urine. It is preferred to consult a doctor if the irritation in the body persists over a long time. Serious increase of the rate of heart beat, sweating, rectal bleeding, dizziness, fainting would indicate that the person is allergic to the medication. However other allergic symptoms may vary from occurrence of rashes, irritation or redness of skin, dizziness, swelling or breathing trouble also demand immediate care. The drug in use should be immediately discontinued and consulted with the physician for safety.