However, all food should have left the stomach within 2 to 4 hours. In the small intestine, digestion continues and absorption occurs. From here on, the time to defecation will vary depending on the time it takes to adequately digest and absorb in the small intestine. This will usually take 5 to 6 hours. The food then enters the colon for further digestion and water reabsorption before defecation. The time from it’s entering the colon to defecation is about 12 to 24 hours. Thus, the time for food to travel from one end to the other probably ranges from about 20 to 30 hours.