After you put food in to your mouth, and swallow it, it travels down your throat through your esophagus (see top of picture). Your esophagus goes through an opening in your diaphragm to your stomach. Your stomach continues the process of digestion, allowing the food to pass to your small intestines, it is in your small intestines that nutrients are absorbed in to your body. After the small intestines, the food (which has now become waste), continues on to your large intestines. This is where the problem of constipation becomes apparent because it is in the large intestines that water is absorbed in to the body from the waste. If the waste stays in the large intestines too long, then the waste becomes too dry, and it becomes harder for the large intestine to move the waste if this happens. On the other side of the coin, if the waste does not stay in the large intestines long enough, then it has far too much water in it, and the outcome of this is diarrhea.