Drink more fluids. Make sure you get enough water every day. You might be tempted to cut back on it if your MS gives you bladder problems. But that makes constipation worse. Make your first beverage of the day something hot, such as hot water or apple cider, or drink 1/2 to 1 cup of prune juice in the morning to get things moving.
Get more fiber. The best way is to eat plenty of fresh fruits and vegetables and whole-grain breads and cereals. Add 2 to 4 tablespoons of unprocessed wheat bran to hot or cold cereal or casseroles, or mix it with applesauce, pancake batter, pudding, muffin batter, milkshakes, or cookie dough. Be sure to drink plenty of liquids, which help the bran work inside you. Your doctor may also recommend that you take a fiber supplement.
Stick to a schedule. Set a regular time when you’ll go to the bathroom. Try going right after meals since eating is a natural way to prompt a bowel movement. Try to wait no more than 2 to 3 days between bowel movements.
Exercise. It’s a great way to get your digestive tract going.
Use stool softeners. But only if your doctor says it's OK.
How to Control Diarrhea
Drink more liquids to make up for what your body is losing. Try water, lemonade or fruit-flavored drinks, fruit or vegetable juice, broth, milk, or soup.
Talk with your doctor or dietitian about how much fiber you should eat.
Eat soft foods that have a lot of liquid, such as sherbet, yogurt, and pudding.
Ask your doctor whether changing your medications might help relieve the diarrhea. But don’t try to take less or stop taking them before you talk to her.
Don't take over-the-counter drugs for diarrhea without talking to your doctor.