Several commonly used herbs can raise blood pressure, some significantly. Licorice root is the most well-documented, but ginseng, ephedra, guarana, arnica, and yohimbe bark also have blood-pressure-raising effects. Whether you’re looking to understand why your blood pressure has crept up or you have low blood pressure and are curious about natural options, knowing which herbs have this effect and how they work is important.
Licorice Root: The Strongest Evidence
Licorice root is the herb most consistently linked to elevated blood pressure. Its active compound, glycyrrhizin, blocks an enzyme in the kidneys that normally converts the stress hormone cortisol into an inactive form. When that enzyme is blocked, cortisol floods receptors that control sodium and potassium balance. The result: your body retains more sodium, loses potassium, and blood pressure rises. Cortisol is 100 to 1,000 times more concentrated in the body than the hormone aldosterone, which normally activates those same receptors, so even partial blockage of the enzyme can produce a meaningful effect.
The World Health Organization sets the toxic threshold for glycyrrhizin at 100 milligrams per day, and a European safety review confirmed that amount as a general upper limit. But some people react to even lower doses depending on individual sensitivity, kidney function, and how long they consume it. Licorice shows up in places you might not expect: herbal teas, throat lozenges, chewing tobacco, and some European and Middle Eastern candies. American “licorice” candy is usually flavored with anise and contains no actual licorice, but imported varieties often do.
Ephedra (Ma Huang)
Ephedra, known in traditional Chinese medicine as ma huang, contains alkaloids that mimic adrenaline. It constricts blood vessels and speeds up heart rate. A review published in the New England Journal of Medicine found that among adverse events tied to ephedra-containing supplements, 47 percent involved cardiovascular problems. Hypertension was the single most common adverse event reported, followed by palpitations and rapid heart rate. More serious complications included stroke, heart attack, and dangerous heart rhythm disturbances.
The FDA banned the sale of ephedra-containing dietary supplements in 2004 due to these risks, but the herb still appears in some imported products and traditional medicine preparations. Its blood-pressure-raising effects can be abrupt and severe, not gradual like licorice. Ephedra constricts coronary arteries and can trigger vasospasm, making it particularly dangerous for anyone with existing heart disease.
Yohimbe Bark
Yohimbe bark, sold widely as a supplement for energy and sexual function, contains yohimbine, a compound that blocks a specific type of receptor on nerve endings. These receptors normally act as a brake on norepinephrine release. When yohimbine removes that brake, norepinephrine floods the system, blood vessels tighten, and blood pressure climbs. Studies in healthy volunteers show yohimbine raises blood pressure even at rest, through both increased nerve signaling from the brain and greater norepinephrine release at nerve terminals throughout the body.
People with autonomic nervous system disorders are especially sensitive to this effect. Yohimbine is actually used medically in some of these patients precisely because it raises blood pressure so reliably. For the average person taking yohimbe supplements, the blood pressure increase may be unwanted and unpredictable, since supplement dosing is poorly standardized.
Ginseng: A More Complicated Picture
Ginseng has a reputation for raising blood pressure, but the reality is more nuanced. Research suggests ginseng tends to raise blood pressure when it’s low and lower it when it’s high. Korean red ginseng, in particular, appears to have a mild blood-pressure-lowering effect at lower doses. At higher doses or in people with normal blood pressure, ginseng may push readings upward.
This biphasic behavior makes ginseng unpredictable. If you’re taking blood pressure medication, the interaction is unclear. The American Heart Association notes that ginseng may interact with calcium channel blockers and other blood pressure drugs, though the clinical significance isn’t fully established. The safest approach is to track your readings if you use ginseng regularly and notice whether your numbers shift in either direction.
Guarana and Caffeine-Containing Herbs
Guarana seeds contain roughly twice the caffeine concentration of coffee beans. Caffeine raises blood pressure temporarily by constricting blood vessels and stimulating the nervous system. A single dose can increase systolic blood pressure (the top number) by 5 to 10 points for a few hours. Guarana appears in energy drinks, weight-loss supplements, and herbal blends marketed for focus and alertness.
The blood pressure effect of guarana tends to be short-lived in people who consume caffeine regularly, since the body develops tolerance. But if you’re caffeine-sensitive or combining guarana with other stimulant herbs, the spike can be larger and longer-lasting. Bitter orange (which contains the stimulant synephrine) is often combined with caffeine in supplement formulas. While synephrine alone may not raise blood pressure and could even slightly lower diastolic pressure, combining it with high-dose caffeine did increase systolic blood pressure in clinical testing.
Arnica
Arnica, commonly used topically for bruises and muscle soreness, can raise blood pressure when taken internally. The Mayo Clinic lists it among herbal supplements that may affect blood pressure or interfere with blood pressure medications. Oral arnica products are less common than topical creams, but they exist in homeopathic preparations and some herbal tinctures. Internal use carries additional risks beyond blood pressure, including digestive irritation and heart irregularities.
Who Faces the Most Risk
The blood pressure effects of these herbs are not the same for everyone. Several factors amplify the risk. People already taking blood pressure medication face the possibility of herb-drug interactions that either raise pressure further or interfere with their medication’s effectiveness. St. John’s wort, for example, can weaken the effects of many heart medications, potentially leaving high blood pressure undertreated even though St. John’s wort doesn’t directly raise pressure itself.
Older adults, people with kidney disease, and those with low potassium levels are more vulnerable to licorice-induced hypertension specifically, because the sodium retention and potassium loss hit harder when kidney function is already compromised. Anyone scheduled for surgery should be especially cautious: several of these herbs can cause dangerous blood pressure swings during and after procedures, and surgeons often recommend stopping herbal supplements at least two weeks before an operation.
How Quickly Effects Appear and Resolve
The timeline varies by herb. Ephedra and yohimbe can spike blood pressure within hours of a single dose, since they act directly on the nervous system. Licorice takes longer, typically days to weeks of regular consumption, because it works by gradually shifting hormone balance. The higher the dose and the longer you take it, the more pronounced the effect.
After stopping, recovery depends on the mechanism. Stimulant herbs like ephedra and yohimbe clear the body within a day or two, and blood pressure typically drops back to baseline quickly. Licorice-induced hypertension can take longer to resolve because the hormone disruption needs time to correct. Case reports describe blood pressure normalization taking anywhere from several days to a few weeks after stopping licorice, depending on how much was consumed and for how long. If blood pressure doesn’t return to normal within a few weeks of stopping an herb, something else may be contributing.