Ten Foods With Absolutely Incredibly Horrible Side Effects

It’s common to expect that medications are going to cause side effects. Some are barely noticeable, and some may be worse than the condition the medication treats. We understand that’s a risk associated with medicine, though.

But what about the things we eat every day?

Sometimes people seem to forget that side effects aren’t limited to the realm of medications. Many foods we consume regularly can have their own effects—some beneficial, some bizarre, and some downright alarming. From mood changes and vivid dreams to serious allergic reactions and unexpected bodily responses, certain foods are capable of surprising us in ways that most people never see coming.

Here are 10 foods with totally unbelievable side effects.

1. Nutmeg – A Kitchen Staple With Hallucinogenic Potential

Nutmeg might seem innocent—after all, it’s something you probably associate with cozy holiday desserts. But when consumed in large amounts, nutmeg can cause hallucinations, dizziness, nausea, and even convulsions.

This is because nutmeg contains a compound called myristicin, which has psychoactive properties. Just a couple of teaspoons can induce serious side effects, and in extreme cases, it can even be toxic.

Moral of the story: Keep your pumpkin spice under control.

2. Licorice – The Sneaky Blood Pressure Spiker

Not everyone is a fan of black licorice, but those who are should be cautious. Eating too much of it can lead to dangerous drops in potassium levels, high blood pressure, and even heart rhythm problems.

The culprit? Glycyrrhizin, a compound found in licorice root, which can interfere with the body’s electrolyte balance when consumed in excess. The FDA has even issued warnings about it.

In fact, consuming as little as 2 ounces of black licorice a day for two weeks can cause health issues, particularly in people over 40.

3. Chili Peppers – Spicy Enough to Cause Euphoria

Most people eat chili peppers for their fiery kick, but did you know they can also cause a natural high? The compound capsaicin, responsible for the heat, triggers the release of endorphins and dopamine, giving some people a euphoric rush similar to a runner’s high.

But there’s a downside: extreme chili consumption can also lead to stomach cramps, nausea, and vomiting. In very rare cases, people have even suffered heart attacks or esophageal rupture after chili-eating contests.

4. Mangoes – The Poison Ivy of the Fruit World

Here’s a surprise: mangoes are related to poison ivy. The skin of the mango contains urushiol, the same compound that causes poison ivy rashes. For some people, touching or eating mango skin can result in an itchy, blistering rash, especially around the mouth and lips.

This reaction is more common in people who are sensitive to poison ivy, oak, or sumac. The mango flesh is usually fine—but be careful during peeling.

5. Beets – The Food That Turns Your Bathroom Into a Crime Scene

If you’ve ever eaten a lot of beets and then visited the restroom only to see bright red urine or stool, you’re not alone—and you’re not bleeding internally either.

This phenomenon, known as beeturia, occurs in some people after consuming beets. It’s caused by the pigment betalain, which can pass through the digestive system and color bodily fluids.

Though harmless, it’s definitely unsettling if you don’t expect it.

6. Grapefruit – The Medication Disruptor

Grapefruit is high in vitamin C and antioxidants, but it can also interfere with a surprisingly large number of medications, including statins, antihistamines, and blood pressure drugs.

The reason? Grapefruit contains compounds called furanocoumarins, which inhibit an enzyme in the gut that breaks down many medications. This can lead to increased levels of the drug in the bloodstream, potentially causing serious side effects.

Always check with your doctor or pharmacist if you’re on medication and craving citrus.

7. Asparagus – The Smelly Side Effect

Asparagus is packed with nutrients, but it comes with a strange after-effect: smelly urine.

Within 15–30 minutes of eating asparagus, many people notice a strong, sulfurous odor when they pee. This is due to the breakdown of asparagusic acid, which creates volatile sulfur compounds.

Even stranger? Not everyone can smell the odor. Some people lack the gene that allows them to detect it, making this one of the most bizarrely selective side effects out there.

8. Poppy Seeds – The Accidental Drug Test Fail

Eating a poppy seed bagel or muffin might seem harmless enough, but it can actually lead to a false positive on a drug test for opiates.

That’s because poppy seeds come from the same plant used to produce opium. Even though the seeds themselves don’t contain narcotics, they can be contaminated with trace amounts of morphine and codeine during harvesting.

While not enough to get you high, it could be enough to raise a red flag on a drug screening.

9. Soy – Hormonal Effects in Large Quantities

Soy is often promoted as a healthy, protein-rich alternative to meat, but it’s also a source of phytoestrogens—plant-based compounds that mimic estrogen in the body.

While moderate soy consumption is generally safe, excessive intake could potentially disrupt hormone levels, especially in those with existing hormone-sensitive conditions. Some studies have linked heavy soy consumption to menstrual irregularities, reduced testosterone in men, and thyroid function suppression.

As with most things, balance is key.

10. Cilantro – The Love-It-Or-Hate-It Herb

Cilantro (also known as coriander) might not cause any physical side effects, but it certainly causes a strong emotional one in a segment of the population. For some people, cilantro tastes soapy or rotten.

This isn’t just picky eating—it’s genetic. A specific gene, OR6A2, affects how people perceive certain aldehyde chemicals found in both cilantro and soap.

So next time someone says cilantro ruins their meal, know that they’re not being dramatic—they’re wired that way.