What Herbs Should Not Be Taken With Lisinopril?

Several widely available herbs can interfere with lisinopril, an ACE inhibitor commonly prescribed for high blood pressure and heart failure. The interactions range from pushing potassium to dangerous levels, to amplifying blood-pressure drops, to quietly altering how much of the drug actually stays in your system. Because lisinopril affects kidney function, electrolyte balance, and blood-vessel tone all at once, the list of problematic herbs is longer than most people expect. The specific risks depend on the herb, and a few deserve more attention than others.

Why Lisinopril Is Particularly Sensitive to Herb Interactions

Lisinopril works by blocking angiotensin-converting enzyme, or ACE, which is part of the hormonal cascade that tightens blood vessels and tells the kidneys to hold onto sodium and water. One well-known side effect is that it raises potassium levels, because the same hormone system it suppresses normally helps the body excrete potassium. That single fact makes any herb that also raises potassium a potential problem. But potassium isn’t the only concern. Because ACE inhibitors lower blood pressure through a specific pathway, any herb that lowers blood pressure through the same or a parallel pathway can stack on top of the drug’s effect and drop your pressure too far. And because lisinopril passes through the kidneys largely unchanged, anything that stresses the kidneys or changes the transporter proteins that shuttle the drug around can shift how much of it ends up in your bloodstream.

Herbs That Raise Potassium

The most medically serious herb-lisinopril interactions involve potassium. High potassium, or hyperkalemia, can cause muscle weakness, numbness, and in severe cases dangerous heart-rhythm disturbances. Because lisinopril already nudges potassium upward by suppressing aldosterone, adding an herb that independently raises potassium creates a compounding risk.

Dandelion leaf is a natural diuretic, but unlike the prescription “water pills” that flush potassium out, dandelion tends to spare potassium, allowing levels to climb. Nettle leaf has a similar potassium-sparing profile. Alfalfa, milkweed, and noni juice are also notably high in potassium content themselves, so consuming large quantities while on an ACE inhibitor can tip the balance. None of these herbs would be flagged by a typical pharmacy interaction checker, which is part of the problem: they fly under the radar because they aren’t classified as drugs.

If you take lisinopril and regularly consume any of these herbs in supplement form or concentrated teas, your doctor can check your potassium with a simple blood draw. The risk is dose-dependent, so the occasional cup of dandelion tea is a different situation from taking dandelion extract capsules daily.

Licorice Root and Glycyrrhizin

Licorice root deserves its own section because its interaction with ACE inhibitors is unusually complex. The active compound, glycyrrhizin, mimics a hormone called aldosterone, causing the body to retain sodium and excrete potassium. That sounds like the opposite of the potassium problem just described, and it is. But the result is still harmful: it works against what lisinopril is trying to do.

A documented case report describes a patient taking two traditional Chinese herbal medicines, both containing glycyrrhizin, who developed pseudoaldosteronism, a condition where the body behaves as though aldosterone levels are sky-high even when they aren’t. The patient’s electrolytes became severely imbalanced. Interestingly, the researchers noted that the ACE inhibitor the patient was also taking appeared to delay the onset of symptoms by partially counteracting the glycyrrhizin, which may have masked the problem until the glycyrrhizin dose accumulated to dangerous levels. Once the herbal products were stopped and potassium was supplemented, the patient recovered quickly.¹

The practical takeaway is that licorice root can undermine lisinopril’s blood-pressure-lowering effect while simultaneously causing its own electrolyte chaos. This applies to real licorice root, the kind found in herbal teas, traditional Chinese medicine formulas, and European-style licorice candy. Most American “licorice” candy is flavored with anise and contains no glycyrrhizin. If a product lists licorice root, licorice extract, or glycyrrhiza on the label, treat it as a potential problem.

Hibiscus and Other Blood-Pressure-Lowering Herbs

Hibiscus tea is widely promoted as a natural way to manage blood pressure, and there is real evidence behind that claim. A clinical trial comparing hibiscus extract head-to-head with lisinopril in people with mild to moderate high blood pressure found that both reduced plasma aldosterone by roughly the same amount: about 30% for lisinopril and about 32% for hibiscus, with no significant difference between the two over the four-week study period.² That’s notable because it means hibiscus acts on part of the same hormonal pathway that lisinopril targets.

Drinking the occasional hibiscus tea while on lisinopril is unlikely to cause a crisis. But if you’re taking concentrated hibiscus capsules or drinking multiple strong cups daily as a deliberate blood-pressure strategy on top of your prescription, you could end up with additive pressure drops. Symptoms of blood pressure falling too low include dizziness when standing up, lightheadedness, blurred vision, and fainting. The risk is highest when you first start lisinopril or when your dose changes.

Hawthorn berry is another herb in this category. It has mild ACE-inhibitory and vasodilatory effects, and it’s often sold as a heart-health supplement. Like hibiscus, hawthorn on its own is relatively gentle, but layered on top of a prescription ACE inhibitor it can push blood pressure lower than intended. Garlic supplements in high doses also have a modest blood-pressure-lowering effect and fall into the same “additive” risk category. Fresh garlic in cooking is not a concern; concentrated garlic extract capsules at therapeutic doses can be.

Ginseng

Ginseng has a complicated reputation in blood-pressure discussions. Some sources warn that it raises blood pressure, others claim it lowers it, and the confusion exists because different types and preparations of ginseng do different things. The most common commercial form, Panax ginseng, has been shown in lab studies to directly inhibit ACE activity. Importantly, that inhibition was additive with the effect of a pharmaceutical ACE inhibitor, meaning the two together produced more ACE suppression than either alone.³

For someone on lisinopril, this means Panax ginseng could amplify the drug’s effect on blood pressure. The clinical significance in a living person (as opposed to cells in a dish) isn’t fully pinned down, but the mechanistic overlap is clear enough to warrant caution, especially at higher supplement doses. American ginseng and Siberian ginseng (eleuthero) have different active compounds and may behave differently, but the research separating their effects from Panax ginseng is limited. If you take any form of ginseng regularly, mention it to whoever prescribes your lisinopril.

St. John’s Wort

St. John’s Wort is one of the most well-documented herb-drug troublemakers in all of pharmacology, and it earns that reputation through a mechanism that’s different from the herbs discussed so far. Rather than directly affecting blood pressure or potassium, St. John’s Wort ramps up the body’s drug-disposal machinery. A clinical study found that it increased expression of P-glycoprotein, a transporter protein that pumps drugs out of cells, by roughly fourfold compared to baseline.⁴

P-glycoprotein is found in the gut lining, liver, and kidneys, all places where it can intercept drugs before they reach the bloodstream or speed their removal. St. John’s Wort also activates liver enzymes that break down many drugs. The net effect is that drug levels in the blood drop, sometimes dramatically. Low concentrations of several drugs, including cyclosporine, theophylline, and digoxin, have been observed in patients who started taking St. John’s Wort.⁵

Lisinopril is not heavily metabolized by the liver the way many drugs are, so the enzyme-induction pathway is less of a concern. But the P-glycoprotein pathway could still matter, and the broader lesson is that St. John’s Wort is a drug-interaction wildcard. If you’re on lisinopril plus other medications, which is common given that high blood pressure often comes with other prescriptions, St. John’s Wort could lower the effectiveness of those other drugs even if its direct effect on lisinopril turns out to be modest.

Herbs That Stress the Kidneys

Because lisinopril is cleared almost entirely by the kidneys, and because ACE inhibitors change blood flow within the kidneys themselves, herbs with nephrotoxic potential pose a compounding risk. If an herb impairs kidney function even slightly, it can slow the clearance of lisinopril and other drugs that depend on the kidneys, leading to higher-than-expected drug levels in the blood. At the same time, lisinopril’s effects on kidney blood flow can make the kidneys more vulnerable to toxic insults from other substances.

Aristolochic acid, found in herbs like birthwort and sometimes present as a contaminant in poorly regulated herbal products, is a well-established kidney toxin. Kava, used for anxiety and relaxation, has raised concerns about both liver and kidney effects. Wormwood, sometimes consumed as absinthe-ingredient supplements, and high-dose willow bark have also been flagged for kidney stress. These aren’t herbs that most people would think of as conflicting with a blood pressure medication, but the kidney is the common link.

The risk here is harder to quantify than the potassium or blood-pressure interactions because it depends on your baseline kidney function, which many people on lisinopril have already had tested. If your kidney numbers are borderline, even mild additional stress from a nephrotoxic herb matters more.

Ephedra and Other Stimulant Herbs

Ephedra (ma huang) is banned in dietary supplements in the United States but still shows up in imported products and traditional medicine formulations. It contains ephedrine, which raises blood pressure and heart rate, directly opposing what lisinopril is trying to achieve. Taking the two together doesn’t create a synergistic toxic reaction per se; it just means your blood pressure medication may not work. The same goes for bitter orange (synephrine), which acts similarly to ephedrine, and yohimbe, derived from tree bark and sold as a libido and weight-loss supplement. Yohimbe can spike blood pressure unpredictably and has been linked to anxiety, rapid heart rate, and even hypertensive emergencies in some case reports.

The frustrating thing about stimulant herbs is that they often appear in multi-ingredient “energy” or “fat-burning” blends where they aren’t prominently labeled. If you’re on lisinopril for blood pressure control, reading the ingredient panel on any supplement marketed for energy, weight loss, or athletic performance is worth the thirty seconds it takes.

How Herbal Products Interfere with Lab Monitoring

An underappreciated problem with taking herbs alongside lisinopril is that some herbal products can distort the lab tests your doctor uses to monitor how the drug is working and whether it’s causing side effects. Kidney function, potassium, and sometimes drug levels of co-prescribed medications are all tracked through blood work. Herbal medicines have been documented to alter test results both by directly interfering with laboratory immunoassays and by changing your body’s physiology in ways that shift what the tests measure.⁵

For instance, if you’re taking a potassium-sparing herb that nudges your potassium up, your doctor might attribute the elevated reading to lisinopril and lower your dose, when the real culprit is the supplement. Or if St. John’s Wort is lowering the blood levels of another co-prescribed medication, the lab result might prompt your doctor to increase that drug’s dose, setting you up for toxicity if you later stop the St. John’s Wort. These aren’t hypothetical scenarios; they’re the kind of cascading mismanagement that happens when herbs aren’t on the doctor’s radar.

Why Your Pharmacist Probably Won’t Catch It

Prescription drug interaction databases are sophisticated for drug-drug pairs. They’re far less reliable for herb-drug interactions. Most pharmacy software will flag lisinopril plus a potassium-sparing prescription diuretic. It will not flag lisinopril plus a daily dandelion root capsule, because the dandelion capsule isn’t entered into the system. Even when pharmacists ask about supplements, the question is usually framed around vitamins and minerals, not herbal teas or traditional medicine formulas.

If you use herbal products regularly, the most effective safeguard is simply to bring the bottles to your next appointment and let your prescriber or pharmacist look at the actual ingredient lists. Many herbal products contain multiple active herbs, sometimes including licorice root or ginseng as minor ingredients in a blend marketed for something else entirely. The ingredient you’re taking intentionally may be fine; the one hiding on line seven of the “proprietary blend” might not be.

When Occasional Use Versus Daily Supplementation Matters

Most of the interactions described here are dose-dependent and time-dependent. A single cup of hibiscus tea or a meal seasoned with garlic is a different risk profile from taking concentrated extract capsules every day for months. The herbs that raise the most concern at any dose are licorice root in substantial amounts, ephedra, and St. John’s Wort, because their mechanisms are potent enough to matter even at moderate intake levels. For herbs like dandelion, nettle, hawthorn, and hibiscus, the risk scales with how much and how often you consume them.

One practical complication is that “herbal supplement” dosing is not standardized the way prescription dosing is. Two different brands of ginseng capsules can contain wildly different amounts of active ginsenosides. A hibiscus tea brewed for three minutes delivers less extract than one steeped for fifteen. This variability makes it hard to draw a clean line between “safe amount” and “risky amount,” which is part of why healthcare providers tend to default to “just avoid it” rather than trying to calibrate a safe herb dose alongside a prescription.

That said, a blanket “avoid all herbs” approach isn’t realistic for people who use herbal products as a meaningful part of their health routine or cultural practice. A more productive strategy is to know which specific herbs carry genuine interaction risks with ACE inhibitors, monitor with blood work when appropriate, and keep your prescriber informed about what you’re actually taking.