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Publication #FCS8622-ENG

Healthy Living: Food Can Affect Your Medicines1

Paulina Wittkowsky and Linda B. Bobroff2

Do the foods you eat affect the way your medicines work? It’s very possible. Certain foods can affect the way prescription and over-the-counter medicines work by delaying, decreasing, or enhancing how much of the drug is absorbed by the body. This can cause unwanted and harmful side effects. Follow the information below to reduce your risk of common food and drug interactions.


It can be dangerous to drink alcohol when you are taking certain medicines. Some drugs that are affected by alcohol are acetaminophens (Tylenol), antihistamines (Benadryl), and ibuprofens (Motrin). Do not drink alcohol when taking these and similar medications. Always read the medicine label, and ask your pharmacist if you are unsure about a possible interaction with alcohol.

Figure 1. 

Be sure to ask your doctor if you can drink alcohol while taking certain medications.



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Grapefruit Juice

Although some prescription medicines, such as those that lower blood pressure or cholesterol, may interact with grapefruit, most medicines do not. Talk to your doctor or pharmacist if you are concerned about a possible interaction. If you want to continue to enjoy grapefruit juice, then your doctor may be able to prescribe a similar but non-interacting medicine that can provide the same benefit without avoiding grapefruit juice.


Some antibiotics, such as tetracycline or fluoroquinolones (Levaquin), should not be taken with milk, other dairy products, calcium supplements, or antacids, such as Tums. The calcium found in these products decreases the body’s ability to absorb the antibiotic.


Vegetables that contain vitamin K, such as spinach, kale, and Brussels sprouts, can reduce the effectiveness of blood thinners (Coumadin). Your doctor or pharmacist will track your blood thinner’s effectiveness during your regular visits. If you keep your intake of these healthy vegetables consistent from day to day, then your doctor or pharmacist can prescribe the right dose of blood thinner for you.

Figure 2. 

Do you take a blood thinner? If so, your doctor or pharmacist will need to know your daily consumption of green leafy vegetables, such as spinach.


Robert Burnside/Hemera/

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Take with Food

Read all medicine bottle instructions carefully. Certain medicines should be taken with food to prevent stomach irritation; examples include ibuprofen (Motrin) and steroids (Medrol or Prednisone).

Ask your doctor or pharmacist for more information on how food can affect your medicines.



This document is FCS8622-ENG (la versión en español de este document es Vida Saludable: Los Alimentos Pueden Afectar sus Medicinas (FCS8622-Span)), one of a series of the Department of Family, Youth and Community Sciences, UF/IFAS Extension. Original publication date June 2004. Revised January 2011 and May 2014. Reviewed February 2017. Visit the EDIS website at This leaflet was originally developed with funding from the Florida Department of Elder Affairs in partnership with state, county, and local agencies.


Paulina Wittkowsky, MS, RD, former education assistant; and Linda B. Bobroff, PhD, RD, LD/N, professor; Department of Family, Youth and Community Sciences, UF/IFAS Extension; Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.