Foods and medications that don’t mix

How drugs and foods interact in your body can be hazardous.

Food Medicine

Food can affect how much medication gets absorbed into the body and how fast it is metabolised. These interactions can render a prescription ineffective, or increase the risk of experiencing dangerous side effects.

Here are some of the most dangerous combinations.

Grapefruit and grapefruit juice
Full of Vitamin C, fibre and potassium, there are many health benefits to grapefruits, but it can also interfere with as many as 85 different prescription medications. Grapefruit juice has an impact on important intestinal enzymes and can mean that more of the medicine will enter your blood stream. This can increase the risk of side effects if you are taking medication for heart conditions, high blood pressure, high cholesterol, infections, epilepsy, depression, anxiety and sleep problems. The exact side effects from interactions vary and depend on the medicine, but some are serious.

Some of the serious side effects that have occurred when certain medicines are taken with grapefruit include:

  • complete heart block (resulting in a very slow heartbeat)
  • torsade de pointes (rapid heartbeats that can lead to sudden death)
  • rhabdomyolysis (severe damage to skeletal muscle that can lead to kidney damage)
  • nephrotoxicity (kidney damage)
  • myelotoxicity (damage to bone marrow)
  • respiratory depression (reduced or slowed breathing).


If you are taking ACE-inhibitors for hypertension or heart problems, then you need to beware of potassium-rich foods, especially bananas. Blood-pressure medications elevate the levels of potassium in the body, and if you add further potassium into the mix you can suffer dangerous heart palpitations.

Kale, broccoli and spinach

If you are taking blood-thinning medication, such as warfarin, leafy green vegetables will work counter to your medication. These foods contain Vitamin K, which promotes blood clotting and will somewhat nullify the effect of medication that works as an anti-coagulant. You don’t have to cut leafy greens out of your diet completely, but you should be careful about overdoing it.


Alcohol interacts with many medicines, including some prescription, pharmacy and complementary medicines. The effects of combining alcohol and medicine depend on the type and dose of the medicine, the amount of alcohol consumed, and also on personal factors, such as genetics, gender and other health conditions. In general, women and older people are more likely to experience such interactions because they are more susceptible to the effects of alcohol. Alcohol can increase the effects of medicines that relax or sedate the body, such as sleeping tablets, anti-anxiety medicines and antidepressant medicines. Some common painkillers can interact with alcohol to cause stomach upsets, stomach bleeding and ulcers.


If you are on antipsychotic medication, coffee can increase the chances of side effects. Also, if you suffer from asthma, consuming a lot of caffeine can reduce the effectiveness of your medication in an emergency.

Have you ever had a bad reaction between food and medicine? What was it and what happened?

Read more at NPS MedicineWise



    To make a comment, please register or login
    16th Oct 2017
    My GP reckons I would need to consume a bucketful of grapefruit juice to affect my heart medication.
    On that reasoning one or two every week or three should be ok methinks.
    16th Oct 2017
    I've been told that licorice can raise blood pressure. Perhaps google this ...
    16th Oct 2017
    Ok, got it worked out. Don't put aside all these great foods, just eliminate the medicine crap. Did this years ago and now heading toward 80 with no issues, pain, mobility problems, BP problems or other ageing worries. I take no medication but just enjoy life to the fullest. And NO, I am not "Lucky" but learnt years ago that medication does not resolve any issues but just creates another problem requiring more medication. Love Glutathione.
    16th Oct 2017
    No Cat, I am certainly not trying to suggest we all throw away medication but do suggest considering what else can be available. For myself I have gone through pain and other worries, sciatica, damaged shoulder, knee pain, loss of cartilage and other ageing issues but have used safe and effective alternatives to eradicate all the problems rather than risk medication or medical procedures. Yes I am lucky in knowing what to do and know full well that while genetics loads the gun; lifestyle (and often medication) pulls the trigger. While I used safe alternatives, far more effective than Morphine, Tramadol or other addictive drugs the base for much of my recovery has simply been raising my Glutathione levels and that is also so easy to do now. As another thought, the alternatives I used do not just “Mask” pain as medication does but in reducing my pain has also created accelerated healing and that is something we should all seek for a greater quality of life. Yes, there are times when medication may be needed. However from my experience and the same experiences of thousands of others my partner and I personally meet and assist around the world the medication should be a secondary consideration – not first.
    16th Oct 2017
    Ok ROB you are apparently able to live well without medications, so pat yourself on the back, BUT there are many of us out there who really do need meds of one sort or another whether we like it or not, for example my friend is in heart failure but carries on a reasonably normal life -in the slow lane - because of medications. So yes you are 'lucky' as she is just one example of life made better with medications. I have a neurological problem in my lower back which comes and goes but when it comes I cannot use my left leg and the pain in hip and leg is literally unbearable even with my high pain tolerance, I need special painkillers to see me through. So please don't make out that everybody who needs medications can just throw them away and be healthy without them.
    27th Mar 2018
    Darn right cat, great if we could ALL get away without Meds
    27th Mar 2018
    I understand your comments Cat and would certainly not suggest people move away from medication they actually need. Because my partner and I work with a particular alternative that is already well proven and very effective we are in constant communication with medial professionals around the world, even doctors in Harley Street London who are also familiar with this product. All are finding this product a much safer and effective product than mainstream medicine as it uses no harmful dugs or substances and has no harmful side effects. So my comment is to simply look about and check if there is something better than traditional medication as this is often not actually fixing the problem but just masking the pain or other issues.

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