Why Does Coffee Make Me Sick

crazy by Editorial Staff | Updated on April 26th, 2023

Do you drink coffee every morning and then feel sick afterward? Do you avoid having coffee because it makes you feel nauseous?

For many of us, a steaming cup of coffee is a near-daily ritual – a reliable comfort in an unpredictable world. The rich, bitter aroma and the unmistakable buzz of the caffeine boost are among the few constants we can count on.

But for some, this same morning pleasure has an unexpected consequence – nausea, headache, restlessness, and other disconcerting symptoms. Understanding why coffee makes some people sick, and how to manage it can be key to making your morning cup a source of pleasure, not pain.

To dig into this common phenomenon, we must look at what happens to our bodies when consuming caffeine. Caffeine is well known for its stimulant effects – it is known to increase alertness, heart rate, and blood pressure, but it also has a range of other effects. It is a vasoconstrictor, which causes the blood vessels in the body to narrow.

It also is an antagonist to adenosine – a neuromodulator that promotes sleep – meaning that consuming caffeine can interrupt natural sleep cycles. All these factors can contribute to the feeling of nausea that many people experience after drinking coffee.

So let’s dive deeper into why coffee makes some of us sick and what strategies can be used to keep it from derailing our mornings.

Reasons why coffee makes me sick

Here are some reasons why you feel sick after consuming coffee.

Caffeine has laxative properties

Caffeine is the main component of coffee that is thought to contribute to its laxative effects. Caffeine has been found to stimulate colon contractions, which is believed that this is why some people experience an increase in their urge to poop after drinking coffee.

Additionally, caffeine increases the amount of gastrin in the stomach, leading to abdominal discomfort and even nausea in some people. It is important to note that not all studies have demonstrated that coffee has a laxative effect and that the results vary greatly among individuals.

The force of the laxative effect also seems to depend on how much coffee was consumed and other factors like a person’s age and health condition.

How much coffee causes laxative effects?

Different amounts of coffee can produce varying levels of laxative effects. A small 2005 study involving 16 participants showed no differences in the force of defecation between those who drank one cup of coffee and those who drank four cups.

However, more recent research suggests drinking up to five cups of coffee daily may cause a laxative effect. For a lucky 30 percent of coffee drinkers, the brew positively affects their digestive system. In contrast, some others may find that consuming more than two cups a day can result in abdominal discomfort and nausea.

It is important to remember that everyone reacts differently to caffeine and coffee, so it is best to listen to your body and adjust your intake accordingly.

Caffeine causes dehydration

Caffeine, a diuretic, is found in coffee. This means that it causes the body to urinate more frequently. When caffeine stimulates the pituitary gland, the kidneys are signaled to remove more fluid from the body. According to studies, consuming coffee can lead the body to urinate more than usual.

This can lead to dehydration, which is the loss of water and electrolytes in the body. Dehydration can be a serious and potentially life-threatening condition if not treated immediately. Dehydration occurs when coffee consumption causes an increase in urination, leading to a decrease in fluid intake.

Moreover, excessive caffeine intake causes nausea, further increasing water loss through vomiting and saliva production. As such, it is important to remember your hydration levels when drinking coffee or espresso and ensure you drink plenty of water throughout the day.

Additionally, coffee’s laxative properties can cause gastrin and abdominal distress, which may lead to nausea and diarrhea. Drinking plenty of water to replace the fluids lost through diuresis is important to avoid feeling sick from coffee.

Coffee’s acidity may cause gastrin and abdominal distress

The acidity of coffee can irritate the gastrointestinal tract, resulting in gastrin and abdominal distress.  Gastrin and abdominal distress are two main factors contributing to feeling sick after drinking coffee.

Gastrin is a hormone produced by the stomach lining, and its release is triggered by coffee. On the other hand, abdominal distress is an involuntary series of muscle movements that can send gastric acid into the esophagus, which can cause heartburn or acid reflux. 

Coffee may lead to diarrhea and feelings of nausea

Caffeine has been shown to stimulate the bowels. It can contribute to nausea, Nausea is a common feeling after drinking coffee, and the acidity of the beverage often causes it. Coffee’s acidity is a major contributor to nausea, though other factors play a role too.

For example, drinking coffee on an empty stomach can aggravate the stomach lining and cause nausea. Additionally, dipotassium phosphate, used to break down coffee acidity, can lead to nausea and diarrhea.

What is Dipotassium Phosphate?

Dipotassium phosphate, a common ingredient in many coffees, is an additive used to decrease the acidity of coffee. It has some laxative properties and can lead to nausea and diarrhea if consumed excessively.

It is also believed to contribute to dehydration and abdominal distress. Hence, the best way to avoid feeling sick from coffee is to limit your daily intake and be aware of how much dipotassium phosphate is included in your coffee. 


Coffee can make people feel sick for a variety of reasons. Coffee is slightly acidic, which can irritate the stomach and cause nausea. Coffee contains caffeine, which has laxative effects and can lead to dehydration.

Additionally, drinking coffee causes the body to release cortisol, which can lead to abdominal distress and nausea. To avoid feeling sick from coffee, limiting your drink, staying hydrated, and being mindful of any existing digestive issues are important.


Editorial Staff

The editorial staff at Crazy Coffee Crave is a team of coffee enthusiasts & Baristas who enjoy the one thing we all think about as soon as we get up in the morning. Trusted by thousands of readers worldwide.