How can I cure constipation in a 16-year old girl.

How long has she been constipated?  If she has been constipated for some time, you might want to have her see a doctor.  

Here are a few suggestions to help her constipation:

1.  Dietary changes: Try avoiding very large meals, drinks with caffeine, spicy or fatty foods, chocolate and some dairy products.  Try adding fiber to her diet.  Eating more fruits and vegetables can also help.  You might want to have her try drinking more water too.

2.  Lifestyle changes: Stress can cause constipation.  Try reviewing her lifestyle and see if there are any stress factors that can be eliminated.  Sleep and exercise can help as well.   

1. Fiber, at least 30mg. The downside to fiber at first is that it may cause excessive bloating and gas in those not used to it. Whole grains, fruits, and vegetables are great sources.

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2. Good Earth has an all-natural, organic tea called "Smooth Move" that produces bowel movements naturally through the use of the Senna leaf. Brew 1 bag for 5-10 minutes every night for a week. Sqeeze out the bag to make sure you get the most out of every mug. Do not take for more than 1 week at a time. This promotes regularity naturally.