7 Most Dangerous Drug and Food Combinations.

Bacon and chocolate. Chili and peanut butter. Some unlikely combinations end up working well together. But when it comes to diet and drugs, the wrong pairing can unwittingly turn into a recipe for disaster.

You don't need a prescription to face these risks--even some common over-the-counter treatments should warrant more careful attention to your menu, says Jen Wolfe, Pharm.D., a D.C.-based pharmacist and consultant with Comprehensive Pharmacy Consulting. Here are seven dangerous duos to dodge.

 1. Limes and cough medicine.

  You may have heard not to drink grapefruit juice with some prescriptions, including cholesterol-lowering statins. But limes, pomelos, and Seville oranges--although not the more-common navel and Valencia varieties--also may block an enzyme that breaks down statins and other drugs, including the cough suppressant dextromethorphan. Because the medication then builds up in your bloodstream, the risk for side effects increases, says Mary Ellen Gullickson, Pharm.D., a pharmacist at Marshfield Clinic in Wisconsin. With dextromethorphan, this includes hallucinations and sleepiness; in statins, you may sustain severe muscle damage. These fruits' effects can linger for a day or longer, so it's best to avoid them and their juices altogether while taking these drugs. (That doesn't mean you can't eat to cure. Try these 5 Fruits That Naturally Fight the Cold & Flu, instead.) And if you're a citrus fiend? Check in with your pharmacist about potential drug interactions, Gullickson recommends.

 2. Dairy products and antibiotics.

  Some antibiotics, including Cipro, bind to calcium, iron, and other minerals in milk-based foods. "This prevents the absorption of the antibiotics, ultimately decreasing their ability to fight infections," Gullickson says. When you get a new prescription for acne or an infection, ask if the drug falls into a class known as tetracyclines or flouroquinolones. If so, avoid milk, yogurt, and cheese 2 hours before and after taking the pills. And talk with your pharmacist about proper timing if you take multivitamins with minerals--they can have a similar effect, Gullickson says.

3. Smoked meats and antidepressants.

 Check the label on your happy pills. If they belong to a class called monoamine oxidase inhibitors or MAOIs--brand names Marplan, Nardil, Emsam, or Parnate--combining them with foods rich in the amino acid tyramine can cause life-threatening spikes in blood pressure, says Gullickson. Unfortunately, the list of no-nos includes not only summer sausage and smoked salmon, but also red wine, sauerkraut, hot dogs, aged cheeses, soy sauce, and draft or home-brewed beer. The good news? Canned or bottled beer probably won't hurt you--and MAOIs have largely been replaced by newer-generation antidepressants, which don't have the same effect on tyramine levels, says Nicole Gattas, Pharm.D., B.C.P.S., assistant professor of pharmacy practice at St. Louis College of Pharmacy.

 4. Chocolate and Ritalin.

  Besides caffeine, chocolate also contains a stimulant called theobromine, says Tom Wheeler, Pharm.D., B.C.P.S., director of pharmacy and pulmonary services at Advocate Illinois Masonic Medical Center in Chicago. (It's the reason chocolate harms dogs--canine bodies can't break it down.) Combining all these stimulants in humans can potentially lead to erratic behavior and seizures. As with caffeine alone, the risks are largely individual. Your best bet: Take note of whether you feel more nervous, irritable, or wired when you combine Ritalin--especially the extended-release forms--with chocolate. If so, increase the amount of time between downing your pill and having dessert. Or, lighten up: "The darker the chocolate, the more caffeine and theobromine it contains," Wheeler says.

 5. Apple juice and allergy meds.

 Nix the nectar from apples, oranges, and grapefruits if you take Allegra (fexofenadine) for hay fever--at least within 4 hours of swallowing the pill, Gullickson advises. These juices inhibit a peptide that transports the drug from your gut to your bloodstream. The resulting lack of absorption makes Allegra up to 70 percent less effective at stopping your sniffling and sneezing, Wheeler says. Other medications also travel with the help of the same peptide; lay off these juices while taking the antibiotics Cipro or Levaquin, the thyroid medication Synthroid, or the allergy and asthma treatment Singulair, Gullickson says.

6. Cinnamon and warfarin.

People taking the blood-thinning medication warfarin--prescribed to prevent or treat clots--have long been warned to keep their intake of vitamin K steady, says Wolfe. This means you shouldn't change your weekly intake of foods like leafy greens or broccoli; because vitamin K plays a key role in clotting, doing so could affect the thickness of your blood. But there's another risk. Cassia cinnamon, the kind on most American grocery-store shelves, contains high levels of a compound called coumarin that can thin blood and potentially cause liver damage, says Eric Newman, M.D., a resident at Mercy Medical Center in Baltimore. If you're on warfarin, switch to Ceylon cinnamon instead, he advises. (Find it at gourmet or spice retailers like Penzeys, where it's $11.29 for 4 ounces).

7. Alcohol and acetaminophen.

 Resist the urge to wash down your Tylenol with a cold one--your body uses the same enzyme to break down the two substances. It's generally best to put 6 hours between drinking booze and taking any medicine containing acetaminophen, including over-the-counter and prescription pain and cold medicines, Gattas says. But the bigger risks come with time: "If you drink alcohol every day, it's probably not a good idea to take Tylenol," Wheeler says. Pairing them regularly can contribute to kidney and liver disease.