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Hibiscus Tea for Blood Pressure: What the Evidence Shows

Hibiscus tea may lower blood pressure slightly, but the trials are small and mixed. Learn what studies found, how people drink it, and who should be careful.

Edited by Anmar ArabPublished 14 October 2026, 7 min read
On this page
  1. Quick answer
  2. What the research says
  3. How people use it
  4. Possible side effects and interactions
  5. Who should be careful
  6. When to see a doctor
  7. Frequently asked questions

Quick answer

Hibiscus tea is a tart, deep-red drink made from the dried calyces (the fleshy cup around the flower) of Hibiscus sabdariffa, also known as roselle. It is popular in many parts of the world, both hot and iced, and it is often promoted for lowering blood pressure.

There is some research behind that claim. A 2021 review of randomised trials found that hibiscus lowered the top (systolic) blood pressure number by several points on average, with the biggest effect in people whose blood pressure was higher to begin with. However, the trials were small, short and very different from one another, and a stricter Cochrane review concluded there is not enough good evidence to say for sure that it works.

Drinking hibiscus tea is generally well tolerated and can be part of a healthy diet. It is not a replacement for blood pressure medicine, and anyone already taking treatment should talk to their doctor before drinking it regularly.

What the research says

A meta-analysis of 17 trials (2021). Ellis and colleagues reviewed 17 randomised controlled trials of hibiscus in Nutrition Reviews. Twelve of them, with around 800 participants in total, measured blood pressure. People included those with high or borderline-high blood pressure, type 2 diabetes, metabolic syndrome or obesity, as well as healthy adults. Seven trials used tea and ten used capsules, at doses ranging from 15 mg to 9 g a day, for 15 to 90 days.

The main findings were:

  • Compared with placebo, hibiscus lowered systolic blood pressure by about 10 mmHg.
  • Across all comparisons, the average fall in systolic pressure was roughly 7 mmHg. The fall in the bottom (diastolic) number was not statistically significant overall.
  • Compared with green or black tea, or with dietary advice alone, there was no clear difference.
  • In a few trials comparing hibiscus with blood pressure medicines, there was no significant difference, but these studies were small and had design weaknesses.
  • People with higher starting blood pressure tended to see bigger drops.
  • LDL ("bad") cholesterol fell slightly, by about 6.8 mg/dL, but other blood fats and blood sugar did not change significantly.

The authors noted important weaknesses: results varied enormously between trials, many studies did not describe how they were blinded, and the hibiscus products used were poorly described. They called for larger trials lasting longer than eight weeks.

A tea trial in the United States (2010). Researchers at the USDA Human Nutrition Research Center on Aging at Tufts University gave 65 adults aged 30 to 70 with borderline or mildly high blood pressure either three cups of hibiscus tea a day or a look-alike placebo drink for six weeks. Systolic pressure fell by 7.2 points in the hibiscus group, compared with 1.3 points with placebo. People who started with the highest readings saw the largest drops. The researchers said more studies were needed.

The Cochrane review (2021). Pattanittum and colleagues looked only for high-quality trials comparing hibiscus with placebo in adults with high blood pressure. Just one trial met their criteria: 60 adults with type 2 diabetes and high blood pressure who took hibiscus extract capsules or placebo for eight weeks. It showed no clear effect on blood pressure, and the certainty of the evidence was rated very low. The reviewers concluded that there is not enough evidence to know whether hibiscus works better than placebo.

Taken together, the rating here is limited: there are encouraging signals from small trials, but the overall quality is weak and the best-controlled evidence is inconclusive.

How people use it

  • As a tea: The best-known tea trial used three cups a day. Other studies described by the Drugs.com professional monograph used an infusion made from about 10 g of dried calyces a day. Most people simply steep dried hibiscus or hibiscus tea bags in hot water; follow the directions on the packet.
  • Hot or cold: Hibiscus can be drunk hot or chilled. If you sweeten it, keep added sugar low.
  • As capsules: Many trials used extracts, but products vary widely in strength and content, and the 2021 review highlighted how poorly many were described. Tea is the simpler, more food-like choice.
  • Alongside other habits: Hibiscus tea is best seen as one small part of a heart-healthy routine. The NHS recommends a balanced diet with less salt, at least 150 minutes of exercise a week, losing weight if needed, limiting alcohol to no more than 14 units a week, cutting back on caffeine, and not smoking.

Effects in the trials were measured over weeks, not hours. The Drugs.com monograph also notes that in one earlier trial, blood pressure rose back to high levels after people stopped drinking hibiscus.

Do not stop or reduce prescribed blood pressure medicine because you have started drinking hibiscus tea. If you take blood pressure medicine, ask your doctor or pharmacist before drinking hibiscus regularly, as the effects may add together.

Possible side effects and interactions

In the 2021 review, hibiscus was generally well tolerated. One trial reported mild stomach upset that settled within a week, and in another, about a quarter of participants dropped out, mainly because they disliked the taste.

Possible interactions listed in the Drugs.com professional monograph include:

  • Blood pressure medicines: hibiscus may add to their effect, so blood pressure may fall more than expected.
  • Chloroquine (an antimalarial): hibiscus may lower its levels in the blood.
  • Paracetamol (acetaminophen): the way the body handles it changed in healthy volunteers, although the practical importance is unknown.
  • Erlotinib (a cancer medicine): a case report describes a skin reaction.
  • Digoxin blood tests: hibiscus tea has caused false results with one type of laboratory test.
  • Other herbs that lower blood pressure: combining them could lower blood pressure too much.

Who should be careful

  • Pregnant or breastfeeding women: the Drugs.com monograph advises avoiding hibiscus because safety information is lacking.
  • People taking blood pressure medicines, chloroquine or erlotinib: speak to your doctor or pharmacist first.
  • People who already have low blood pressure or often feel dizzy or faint when standing up: a further drop may not be welcome.
  • Anyone with high blood pressure that has not been checked by a professional: get a proper diagnosis rather than trying to manage it yourself.

When to see a doctor

High blood pressure usually causes no symptoms, so the NHS recommends getting it checked if you think you may be at risk, and every five years if you are 40 or over. It is considered high at 140/90 or above when measured by a healthcare professional, or 135/85 or above at home.

The NHS advises contacting NHS 111 or an urgent care service if you have:

  • Frequent headaches
  • Blurred vision
  • Chest pain that comes and goes
  • Other symptoms you think may be caused by high blood pressure

Call emergency services (999 in the UK) straight away for sudden chest pain or pressure that does not go away, pain spreading to the arms, neck, jaw, stomach or back, or chest pain with sweating, feeling sick, light-headedness or shortness of breath. Do not drive yourself to hospital.

Frequently asked questions

Can hibiscus tea replace my blood pressure tablets?

No. The evidence is not strong enough, and stopping prescribed treatment can be dangerous. If you want to try hibiscus tea, tell your doctor so they can watch your readings.

How many cups of hibiscus tea a day were used in studies?

The best-known tea trial used three cups a day for six weeks. Other trials used different amounts and preparations, so there is no agreed dose.

Does hibiscus tea lower cholesterol?

The 2021 review found a small fall in LDL cholesterol, but this result was not robust: removing a single trial changed it. It should not be relied on to manage cholesterol.

Is hibiscus tea safe to drink every day?

For most healthy adults, hibiscus tea appears to be well tolerated in the amounts used in studies. Pregnant or breastfeeding women, and people taking blood pressure medicines or the other medicines listed above, should check with a health professional first.

References

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