What NOT to Eat While Taking Antibiotics

Antibiotics, also known as antimicrobials, are medications that eliminate or inhibit the growth of bacteria. The bacteria that cause illness, such as strep throat or urinary tract infection, are not the ones you want in your body. Antibiotics help kill those bacteria by stopping the production of proteins that they need to survive. This can either eliminate the bacteria or prevent their reproduction.

Related: What Are Antibiotics Made Of?

Antibiotics are typically taken in the form of tablets, capsules, or liquids. While they are extremely effective at treating bacterial infections, antibiotics have a substantial effect on your immune system. They have a particular impact on the balance of good bacteria in the body, which is a component of your immune system that aids in the defense against harmful bacteria.


Taking antibiotics is unavoidable when you have a bacterial infection. However, antibiotics are a double-edged sword. While they kill the bacteria we need to get rid of in our bodies, they may also harm the good bacteria. This can result in the nausea, gas, and diarrhea that many people experience while on antibiotics. Eating a healthy, balanced diet will protect the healthy bacteria that live with you every day when you’re on antibiotics. Read our article on the foods you should eat while taking antibiotics for more information.

It’s also helpful to know that certain foods may interfere with your antibiotic treatment. Continue reading to learn about the things you should avoid while taking antibiotics. 

1. Sugary foods

sugary drinks

Studies show that excess sugar can feed certain types of bad bacteria. Furthermore, sugar can also inhibit our white blood cells' ability to destroy bacteria. According to research, the ability of white blood cells to entrap bacteria decreases significantly after people consume various types of sugar. The effect of the decrease in this type of immunity lasts up to five hours after eating the sugary product.

Therefore, it’s advisable to stay away from foods or beverages high in added sugar, such as sodas, fruit juices, cakes, and cookies, while you’re on antibiotics.

2. Grapefruit

grapefruit juice

While grapefruits are beneficial for health as they contain vitamin C and potassium, research shows that it can be harmful to consume this fruit or its juice while taking antibiotics.

Many drugs are broken down or metabolized in the small intestine by an enzyme called CYP3A4. A report published by the Centers for Disease Control and Prevention suggests grapefruit juice may inhibit the action of intestinal CYP3A4 enzymes. As a result, more of the drug enters the blood and stays in the body longer rather than being digested.

If you consume grapefruit while taking antibiotics, your body may not be able to properly break down the medication. In one study of six healthy men, it was discovered that drinking grapefruit juice while taking the antibiotic erythromycin increased the amount of the antibiotic in the blood compared to taking it with water.

Related: Warning! A Whole Course of Antibiotics Could be Dangerous!

3. Foods supplemented with calcium


Calcium-fortified foods may potentially have an impact on how well antibiotics are absorbed. The absorption of various antibiotics, such as ciprofloxacin (Cipro) and gatifloxacin, has been shown to be reduced by foods containing calcium.

Certain antibiotics, such as tetracyclines and fluoroquinolones, can bind to calcium, which prevents your body from absorbing it. So, eating foods high in calcium with antibiotics can reduce the effectiveness of the treatment course.

That being said, we should also keep in mind that yogurt, a calcium-rich product, will be beneficial to our gut while on antibiotics because the probiotics in it will help prevent unwanted side effects such as diarrhea. It is advisable to space these foods out at least two hours after taking your antibiotic and six hours before your next dose.

4. Alcohol


Although alcohol has no significant impact on the effectiveness of most antibiotics, consuming too much of it during antibiotic treatment may result in certain side effects, such as stomach upset, dizziness, and sleepiness.

According to the Mayo Clinic, you should never mix alcohol with the following antibiotics:

  • Metronidazole (Flagyl)
  • Tinidazole (Tindamax)
  • Sulfamethoxazole and trimethoprim (Bactrim)
  • Linezolid (Zyvox)

Consumption of any amount of alcohol while taking these medications may cause flushing, headaches, nausea, and vomiting, as well as rapid heartbeats.

Remember that certain mouthwashes, cough medicines, and cold medications also include alcohol. Hence, it is imperative to check the label of these products and avoid them while taking these antibiotics.

It is also worthwhile to keep in mind that drinking alcohol interferes with sleep and hydration. These physiological processes are essential to recovering from a bacterial infection. Due to these factors, it’s advisable to refrain from drinking alcohol entirely until you've finished your antibiotic course.

Related: It’s Essential that We Debunk These Antibiotic Myths!

5. High-fat foods

fatty foods

There is long-established evidence that high-fat diets are associated with a range of health issues, including weight gain, obesity, higher cholesterol levels, and an increased risk of heart disease. A recent study now suggests that combining a Western-style high-fat diet with antibiotic use significantly increases the risk of developing pre-inflammatory bowel disease (pre-IBD).

According to this study, approximately 11% of the world's population suffers from irritable bowel syndrome (IBS). The symptoms of this condition include recurring episodes of abdominal pain, bloating, and changes in bowel habits. The pre-IBD stage of IBS is marked by mucosal inflammation and changes in the composition of the gut's microbial population.

Related: 9 Natural Antibiotics That Grandma Used To Swear By!

Andreas Baumler, lead author of this research and professor of medical microbiology and immunology, said: “Our study found that a history of antibiotics in individuals consuming a high-fat diet was associated with the greatest risk for pre-IBD.”

Our gut requires good bacteria as well, but combining a high-fat diet with antibiotics can disrupt this, say the study’s authors, as it can harm the intestinal lining. They interfere with cell function and cause oxygen leakage into the stomach. Because good bacteria cannot thrive in a high-oxygen environment, this causes a bacterial imbalance in the body.

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