Have you noticed it for yourself: the sudden urge to poop after drinking your morning cup of joe? This phenomenon is quite prevalent among coffee drinkers and has even been studied (with small surveys being taken as samples for further scientific investigation).

Researchers have concluded that both caffeinated and decaf coffee can make you poop, though the exact reason remains unknown. Evidence points towards caffeine acting as a vasodilator, dilatting all blood vessels to increase circulation throughout your body – including colon and intestinal muscles which then trigger contractions which propel feces toward your anus.

Coffee’s fatty acids may help induce bowel movement by expanding the surface area where bacteria can attach themselves and multiply, leading to an involuntary motion that leaves your stool with either an aroma similar to coffee, or metallic taste due to iron produced when bacteria break down proteins in the colon.

Noting the potential risks, it is important to realize that regularly consuming more than 400 milligrams (four cups) of caffeine a day (that’s equivalent to two coffee drinks) could lead to dependence, as well as discomfort in the form of diarrhea or stomach upset. Therefore, drinking water and maintaining a balanced diet is also vitally important in order to avoid constipation and other related health problems.