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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. Food 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 the most common food and drug interactions.


Drinking alcohol when you are taking certain medicines can be very dangerous and should be avoided. Some drugs that are affected by alcohol are acetaminophen (such as Tylenol™), antihistamines (such as Benadryl™), and ibuprofen (such as Motrin™).


Grapefruit juice increases the effect of some medicines such as blood pressure medications. It is best not to take medicine with grapefruit juice. If you would like to have a glass of grapefruit juice, drink it at least two hours before or after you take your medicine.


Some antibiotics, like tetracycline, should not be taken with milk, other dairy products, or calcium supplements. 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 (such as Coumadin™).


Read all instructions on the bottle carefully. Certain medicines should taken with food to prevent stomach irritation. Examples include ibuprofen (such as Motrin™) and certain diuretics (such as Aldactone™).

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



La versión en español de este document es Vida Saludable: Los Alimentos Pueden Afectar sus Medicinas (FCS8622-Span). This is document FCS8622, one in a series of the Department of Family, Youth and Community Sciences, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611. First published March 2004. Revised January 2011. This leaflet was originally developed with funding from the Florida Department of Elder Affairs in partnership with state, county, and local agencies. Visit the EDIS website at


Paulina Wittkowsky, MS, RD, former education assistant, and Linda B. Bobroff, PhD, RD, LD/N, professor; Department of Family, Youth and Community Sciences; Institute of Food and Agricultural Sciences University of Florida; Gainesville 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.