Many people turn to natural supplements as the solution to a number of health issues, from poor sleep to stress to inflammation. But as a conscious consumer, it’s crucial to remember that most supplements come with risks. Just because something is natural doesn’t mean it’s safe—especially when combined with prescription medications. According to experts, some of the most popular herbal supplements can interfere with how medications work in your body, leading to potentially dangerous or even life-threatening consequences.
“Herb-drug interactions are common and can be really, really serious, and not many people know about them,” says Janelle Bober, MS, RDN from Dietitian Live. “Always talk to your doctor, avoid self-prescribing things, especially when using medications with high interaction rates like warfarin or antidepressants.” Below, we’ll dive into five combinations that can have harmful interactions.
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1. Ginseng and Antidepressants
Ginseng is often seen as a natural energy booster, but if you’re taking antidepressants—especially SSRIs, SNRIs, or tricyclics—it’s best to steer clear of this supplement, Bober says.
"Ginseng is serotonergic, meaning it produces serotonin, so it has those types of properties and it may increase our serotonin levels and enhance antidepressant effects," she explains. That might sound great for those seeking relief from low mood, but in reality, it can trigger serotonin syndrome, or the buildup of too much serotonin in the body, leading to symptoms like agitation, confusion, rapid heart rate, and high blood pressure. "The impacts after you experience serotonin syndrome can be really negative because your serotonin then plummets really far and can actually increase your depression symptoms and experiences," Bober explains.
Unless your provider specifically recommends it, Bober advises avoiding ginseng altogether if you're on antidepressants. "Look for different alternatives like magnesium, for example, or just use it under medical supervision."
2. Ginseng and Blood Thinners
Ginseng doesn’t just impact antidepressants. It can also interfere with blood thinners like warfarin or other anticoagulants and antiplatelet medications.
"What happens is that it actually decreases the effect of these medications, and it can decrease our ability to thin our blood," Bober explains. "If we have less coagulation, it can increase the risk of blood clots and actually lead to possible stroke."
If you’re taking any kind of blood thinner, it's important to talk to your doctor before adding ginseng to your routine, and monitor your medication closely.
3. Ginkgo Biloba and Blood Thinners
Ginkgo is a popular supplement often used for memory support, but this is another natural option that can spell trouble if you’re on blood-thinners like aspirin, warfarin, or clopidogrel.
"Ginkgo actually impairs platelet aggregation," says Bober. "When combined with blood thinners... it significantly increases your bleeding risk." That can be especially risky for people with bleeding disorders or anyone preparing for surgery.
Instead of ginkgo, Bober recommends options like turmeric or ginger, which may offer similar benefits without the same level of risk.
4. Garlic and Blood Thinners or NSAIDs
Garlic in your pasta? Great. Garlic in supplement form? Could be risky—especially if you're taking NSAIDs, aspirin, or warfarin.
"Garlic can increase bleeding risk by reducing the stickiness of our platelets," Bober says. This raises the risk of issues like spontaneous bruising, gastrointestinal bleeding, or dangerous complications before surgery.
Stick to using garlic as a dinner ingredient. If you do take it is supplement form, keep your doses low—"around 600 mg per day," Bober advises—and always check with your doctor if you're on a medication that affects clotting.
5. St. John’s Wort and Antidepressants
St. John’s Wort is often used to help treat mild depression, so it may sound like a good idea to pair it with an antidepressant. But in reality, this combo could be dangerous.
"It basically interacts with one of our CYP metabolizing systems in our liver and it creates P glycoprotein, and this lowers blood levels of medications, namely antidepressants," says Bober. On top of reducing effectiveness, it can also increase your risk of serotonin syndrome, similar to ginseng.
"This is one of the most studied and researched combinations," she emphasizes. The bottom line: don’t combine it with antidepressants, and opt for safer options instead—like herbal teas or magnesium.
Bottom Line
All in all, it's always important to be mindful of what you're putting into your body, especially when you're taking prescription medication. "You always want to stay up to date on labs," says Bober. "If you're combining supplements that do have high-risk interactions, monitor your labs regularly. Go see your doctor, talk to your doctor, and just make sure you're keeping track of any new or worsening symptoms," she concludes.
