When you drink coffee, several reactions occur in your body. It can make you more alert and boost your cognitive function.

Coffee can also cause contractions in your colon that help food move through your digestive system causing an urge to poop.

Understanding the relationship between coffee and your digestive health may help you manage your bathroom habits and promote regularity.

If coffee is a regular part of your diet, you may notice it affects your digestive system and potentially increases your urge to poop. Part of this is due to peristalsis, the muscle contractions and relaxations in your colon shortly after eating or drinking. Coffee can stimulate these contractions, speeding up the process.

Research suggests that within four minutes of drinking coffee, your body will start moving any stool in your colon toward your rectum, increasing your urge to have a bowel movement. Coffee also stimulates gastrin, a hormone responsible for gastric motility, the movement of food through your digestive tract.

Studies have also found that the caffeine in coffee may stimulate cholecystokinin production. This hormone increases bile production in your small intestine and may help push waste through your body more quickly.

All these processes working together can increase your urge to poop.

Does Adding Dairy Increase the Urge?

What you add to your coffee may also affect your urge to poop. In particular, people who are lactose intolerant or sensitive to dairy may notice more pronounced digestive effects. In addition to needing to poop, this sensitivity can sometimes cause diarrhea and bloating. For this reason, adding dairy to your coffee can intensify your urge to use the bathroom.

There’s also some evidence that adding an artificial sweetener like Splenda to coffee may affect digestion and increase your need to poop. 

Does Time of Day Matter?

The time of day can also affect how quickly coffee makes you feel like you have to go. Research shows that drinking coffee in the morning may have a more noticeable impact on the urge to poop.

Researchers suggest this may be because your gastrointestinal system is more active in the morning. Your body’s circadian rhythm (sleep-wake cycle) is transitioning you from sleep to awake, increasing your gastrointestinal activity to prepare for food.

Coffee contains more than 1,000 different compounds, including caffeine. One cup of coffee typically contains about 80-100 milligrams of caffeine.

While the caffeine in coffee is not the only thing increasing your urge to poop, it does play a role. Caffeine can stimulate contractions in your colon. It also increases pressure in your anus, which can cause you to feel like you need to poop.

An older study found that caffeinated coffee makes the colon 60% more active than water and 23% more active than decaf coffee.

Digestive Effects of Decaf Coffee

While caffeine plays a role in increasing your urge to poop, it is not the only compound in coffee contributing to this effect. Some people still experience an increased urge to have a bowel movement after drinking decaffeinated coffee.

The United States Food and Drug Administration (FDA) recommends not exceeding 400 milligrams of caffeine daily, or about 4 cups of coffee. You can drink half-decaf coffee to reduce caffeine intake while still experiencing digestive effects.

Not everyone will experience the urge to go after drinking coffee. One study found that only about one-third of people experience this phenomenon.

Your sex and underlying medical conditions can play a role in how your body reacts to coffee. For instance, women may experience the urge to poop after drinking coffee more often than men.

An older study found that out of the people who reported the urge to defecate after drinking coffee, 63% were women. This may be because women are more likely to experience irritable bowel syndrome (IBS) than men. Menstruation, which can cause digestive symptoms, may also play a role.

If you want to reduce the urge to go after drinking coffee, here are a few tips to try:

• Drink coffee later in the day when your gastrointestinal system is less active
• Switch to a lactose-free creamer or milk alternative if you suspect a dairy sensitivity
• Drink fewer cups of coffee
• Switch to decaf coffee or drink decaf part of the time

Talk with a healthcare provider if your bowel movements seem unmanageable. In some cases, your need to go may be related to an underlying health condition like IBS.

About one-third of people experience an increased urge to poop after drinking coffee.

Coffee can stimulate muscle contractions and gastric motility in your colon, affecting digestion and inducing a bowel movement.

To reduce the urge to go, consider decreasing your daily consumption, switching to a nondairy creamer, or drinking coffee later in the day.