When you’re sick, it’s natural to want the comforting foods and drinks that you’re used to. For many people, that includes coffee.

For healthy people, coffee has few negative effects when consumed in moderation. It may even offer some health benefits, as it’s rich in antioxidants. Plus, the caffeine may provide some slight fat-burning benefits (1, 2).

However, you may wonder whether coffee is safe to drink when you’re sick. The drink has pros and cons depending on the type of illness you’re dealing with. It can also interact with some medications.

This article examines whether you can drink coffee while you’re sick.

Morning coffee is non-negotiable for many people who find that its caffeine content helps wake them up. In fact, even decaf coffee can have a mild stimulant effect on people due to the placebo effect (3).

For many coffee drinkers, this perceived increase in energy is one of the key benefits of coffee, as well as one reason you may choose to drink it when you’re sick.

For example, it can give you a boost if you’re feeling sluggish or fatigued but still well enough to go to work or school.

Plus, if you’re dealing with a mild cold, coffee may help you get through your day without causing any significant side effects.


Coffee can give you an energy boost, which can be helpful if you’re mildly under the weather but well enough to go to work or school.

Coffee can also have some negative effects. The caffeine in coffee has a diuretic effect, meaning it can draw fluid out of your body and cause you to excrete more of it through your urine or stool (4).

In some people, coffee intake may lead to dehydration as a result of diarrhea or excessive urination. However, some researchers note that caffeine intake at moderate levels — such as 2–3 cups of coffee per day — has no meaningful effect on your fluid balance (5, 6, 7).

In fact, regular coffee drinkers are more likely to become accustomed to the diuretic effect of coffee, to the point that it doesn’t cause them any problems with fluid balance (5).

If you experience vomiting or diarrhea — or if you have the flu, a severe cold, or food poisoning — you may want to avoid coffee and choose more hydrating drinks, especially if you’re not a regular coffee drinker.

Some examples of more hydrating beverages include water, sports drinks, or diluted fruit juices.

However, if you’re a regular coffee drinker, you may be able to continue drinking coffee with no increased risk of dehydration when you’re sick.


In people who are severely sick or experiencing vomiting or diarrhea, coffee may compound these issues and lead to dehydration. However, regular coffee drinkers may not have these issues.

Coffee is acidic, so it may cause stomach irritation in certain people, such as those have an active stomach ulcer or acid-related digestive issues.

According to a study in 302 people with stomach ulcers, more than 80% reported an increase in abdominal pain and other symptoms after drinking coffee (8).

However, another study in over 8,000 people found no relationship between coffee intake and stomach ulcers or other acid-related gastrointestinal problems like intestinal ulcers or acid reflux (9).

The link between coffee and stomach ulcers seems to be highly individual. If you notice that coffee causes or worsens your stomach ulcers, you should avoid it or switch to cold brew coffee, which is less acidic (10).


Coffee may further irritate stomach ulcers, but research findings are not conclusive. If coffee irritates your stomach, you should avoid it or switch to cold brew, which is not as acidic.

Coffee also interacts with some medications, so you should avoid coffee if you’re taking one of these.

Particularly, caffeine can strengthen the effects of stimulant drugs like pseudoephedrine (Sudafed), which is often used to help alleviate cold and flu symptoms. It can also interact with antibiotics, which you may receive if you have a bacterial infection of any kind (11, 12).

Again, regular coffee drinkers may be able to tolerate these medications while drinking coffee, as their bodies have become accustomed to its effects (13).

However, you should speak with a healthcare professional before choosing to drink coffee with these drugs.

Another option is to drink decaf coffee while taking these medications, as the caffeine in coffee is what causes these interactions. While decaf contains trace amounts of caffeine, such small amounts are unlikely to cause drug interactions (14).


The caffeine in coffee may interact with stimulant drugs like pseudoephedrine, as well as antibiotics. You should talk to a healthcare provider before drinking coffee while taking these drugs.

Although coffee in moderation is generally harmless in healthy adults, you may choose to avoid it if you’re sick.

It’s fine to drink coffee if you’re dealing with a mild cold or illness, but more severe illnesses that are accompanied by vomiting or diarrhea can lead to dehydration — and drinking coffee may compound these effects.

However, if you’re a regular coffee drinker, you may be able to continue drinking coffee during a more severe illness with no adverse effects.

You may also want to limit coffee if you notice that it causes or irritates stomach ulcers.

Finally, you should also avoid coffee — or caffeinated coffee, at least — if you’re taking any medications that may interact with caffeine, such as pseudoephedrine or antibiotics.

It’s best to consult a healthcare provider if you have any concerns about drinking coffee while you’re sick.