Coffee makes you poop primarily because it contains caffeine, a natural stimulant that activates contractions in the colon and intestinal muscles. These contractions help push waste through the digestive system faster, leading to an increased urge for a bowel movement. Research shows that caffeinated coffee makes the colon about 60% more active than water and 23% more active than decaf coffee. However, decaffeinated coffee can also stimulate bowel movements due to other compounds like chlorogenic acids that increase stomach acid production, aiding gut motility. Additionally, coffee stimulates the release of hormones such as gastrin and cholecystokinin, which enhance digestive muscle contractions and bile production to help move waste through the intestines. This gastrocolic reflex, where drinking or eating activates colon activity, combined with the body's morning increased gut activity due to circadian rhythms, can make coffee a strong trigger for pooping, especially soon after waking up. In summary, coffee's effect on making you poop involves its caffeine content stimulating colon contractions, other compounds stimulating stomach acid and digestive hormones, and natural bodily rhythms that prime your digestion in the morning.