Within a few minutes after a meal reaches the stomach, it begins to pass through the lower valve of the stomach.

After the first hour the stomach is half-empty, and at the end of the sixth hour none of the meal is present in the stomach. The meal goes through the small intestine, and the first part of it reaches the cecum in 20 minutes to 2 hours.

At the end of the sixth hour, most of it should have passed into the colon; in 12 hours, all should be in the colon. Twenty-four hours from the time when food is eaten, the meal should reach the rectum. However, part of a meal may be defecated at one time and the rest at another.