When you take medicine, you are likely aware that it may interact badly with alcohol or other drugs. And, often, those warnings are on the prescription label.

But many people don’t realize that some medications can have dangerous, even fatal,
consequences when mixed with the wrong foods.

“This is a big issue and a lot of people aren’t aware of it,” says Jack Fincham, professor of pharmaceutical and administrative sciences at the Presbyterian College School of Pharmacy in Clinton, South Carolina.

Here are six of the most common and dangerous food-drug combos.

If you’re taking: Warfarin.

Don’t eat: Leafy greens.Kale, beet greens, broccoli rabe, Swiss chard, collard greens, mustard greens, spinach, and other leafy greens are loaded with vitamin K, which plays a major role in blood clotting. Warfarin (Coumadin) is a powerful blood thinner that prevents blood clots. Eat too many leafy greens while you’re taking this anticoagulant drug and you’ll compromise warfarin’s anticlotting effects, increasing your risk of developing a blood clot.

“You don’t have to totally eliminate [these foods] but you should limit your intake if you’re taking Coumadin,” Fincham says.

If you’re taking: A statin drug.

Don’t eat: Grapefruit. “A compound in grapefruit and grapefruit juice binds with the
active ingredient in statin drugs so they don’t work as well,” Fincham tells Newsmax Health.

It’s best to “take the statin drugs at bedtime because most cholesterol is formed when your body is at rest,” Fincham says. This way, you can safely eat half a grapefruit in the morning.

If you’re taking: Blood pressure drugs.

Don’t eat: Dried fruits. If you eat potassium-rich foods potassium (such as dried fruits,
avocados, bananas, oranges, and leafy greens) or salt substitutes while taking blood pressure medication that are ACE inhibitors or diuretics, you could end up with dangerously high levels of potassium. This can lead to an irregular heartbeat or heart
palpitations.

If you’re taking: Antibiotics.

Don’t eat: Dairy products or calcium-fortified foods. The calcium salts in milk, yogurt, cheese, and calcium-fortified foods (like OJ) impair the body’s ability to absorb antibiotics such as those in the tetracycline class or ciprofloxacin, which could compromise the drug’s ability to cure your infection.

Your best bet is to consume dairy products or calcium-fortified foods an hour before or two hours after taking one of these antibiotics, Fincham says.

If you’re taking: Levothyroxine or digoxin.

Don’t eat: High-fiber foods. Soybean flour, walnuts, and other high-fiber foods can make levothyroxine (used to treat an underactive thyroid gland) less effective. Tell your doctor if you eat a lot of these foods; he or she may need to adjust your dosage of the drug.

If you take digoxin (used to treat heart failure), foods that are rich in fiber could decrease levels of the drug in your body. Your best bet is to take digoxin at least two hours before or after consuming foods that are loaded with fiber.

If you’re taking: MAO inhibitors or anti-mycobacterial drugs.

Don’t eat: Aged cheeses. If you consume foods that are rich in tyramine (such as smoked meats or fish, fermented or pickled foods, aged cheeses, dried fruits, avocado,
soy sauce, fava beans, or chocolate) along with MAO inhibitors (used to treat depression or Parkinson’s disease) or anti-mycobacterial drugs (used to treat the bacteria that cause tuberculosis), and you could experience a dangerous spike in blood pressure.

“This can lead to a hypertensive crisis,” Fincham says. “This risk is not something that’s going to go away,” so you need to avoid these foods while taking these meds.

The full version of this article appeared in Health Radar newsletter. To read more, click here.