Does hibiscus tea lower blood pressure?

Probably by a few points, more so when pressure starts higher, on evidence from small trials that disagree with each other. A 2022 meta-analysis of randomized trials in 819 people found hibiscus lowered systolic pressure by 7.10 mm Hg (95% CI 1.20 to 13.00), with heterogeneity of 95 percent. The fall in diastolic pressure did not reach significance. The one placebo-controlled trial of brewed tea, in 65 adults, found three cups a day for 6 weeks lowered systolic pressure by 7.2 mm Hg against 1.3 on placebo.

Unsettled. Most reviews find a drop, and the strictest one does not accept the trials behind it. The 2021 Cochrane review, which required placebo or no treatment and diagnosed hypertension, kept one trial of 60 people with type 2 diabetes and said the evidence is insufficient to determine whether roselle lowers blood pressure. The other meta-analyses pooled small, short trials with very different doses and controls. A real effect of a few mm Hg is plausible. Its size is not settled.

What the trials found

The pooled analyses

In the 2022 meta-analysis, the trials compared hibiscus with another tea, placebo or a prescribed diet. Against placebo alone systolic pressure fell by 10.05 mm Hg (95% CI 2.51 to 17.58), in a small set of trials with wide intervals. Allocation was described as concealed in only 6 studies. Hibiscus at 1 g a day or less did not lower systolic or diastolic pressure, and the authors say there are too few trials to propose a dose or a duration.

Earlier, a 2015 meta-analysis of 5 trials in 390 people found systolic pressure fell by 7.58 mm Hg (95% CI 5.46 to 9.69) and diastolic by 3.53 (95% CI 1.89 to 5.16), with a larger effect at higher starting pressure. It used a fixed-effect model on five small trials. A 2022 meta-analysis of 13 trials in 1205 people with mild to moderate hypertension found drops of 6.67 mm Hg systolic and 4.35 diastolic against placebo, and its abstract gives no intervals. The largest synthesis, a 2025 umbrella review with 26 trials and 1797 people, found pressure fell more with higher doses, against placebo and other teas.

Against blood pressure drugs

In 4 trials that compared hibiscus with captopril, lisinopril, ramipril or hydrochlorothiazide, the difference between them was 2.13 mm Hg systolic (95% CI -2.81 to 7.06) and did not reach significance. No significant difference does not prove the two work equally. In one of those trials 250 mg of hibiscus did less than 10 mg of lisinopril. Nothing here supports swapping a prescribed drug for tea.

Tea, rather than extract

The placebo-controlled trial that tested the drink people actually make gave 65 adults aged 30 to 70, with high-normal or mildly high pressure and no blood pressure medicine, three 8.1 fl oz (240 mL) servings of brewed hibiscus tea a day. After 6 weeks systolic pressure had fallen by 7.2 mm Hg against 1.3 on placebo (P = 0.030). Diastolic fell by 3.1 against 0.5 and did not reach significance. In 100 mildly hypertensive people with type 2 diabetes, sour tea three times a day for 4 weeks took systolic pressure from 123.1 to 116.8 mm Hg, and green tea took it from 119.4 to 114.8. That trial had no placebo arm, so it cannot say how much of either fall came from the tea.

Who should be careful

Side effects in the trials were rare and mild, and the trials were short, up to 90 days. Across the 2022 meta-analysis only one study reported any, mild stomach symptoms on 1 g of extract a day that passed within a week. The 2025 umbrella review found a small rise in the liver enzyme AST, which it judged clinically insignificant, and no rise in adverse events. It also says long-term safety at therapeutic doses needs monitoring.

Not for everyone. If you take warfarin, tell the person managing it before you start drinking hibiscus tea. A 2026 case report described a 59-year-old woman with a mechanical heart valve whose INR, the measure of warfarin effect, rose sharply after she began drinking it. It settled once she stopped, held warfarin and was given vitamin K. That is a single case, where a link is possible and not proven.

We found no trial, review or official position on hibiscus tea in pregnancy or while breastfeeding, and no record for it in a drug interaction database or the LactMed database. That is an absence of evidence, and it does not mean the tea is safe in pregnancy. If you take medicine for blood pressure, the tea trial above left such people out, so any change belongs in a conversation with whoever prescribes it.

What expert bodies say

We found no expert body with a position on hibiscus for blood pressure. The FDA and the NIH are silent on it, and we could not retrieve a page from the US National Center for Complementary and Integrative Health or the European Medicines Agency herbal committee. The Cochrane review above is the most cautious independent reading, and it found the evidence insufficient.

How we searched

What would change this answer

• A larger and longer placebo-controlled trial of brewed tea, at an amount people drink. The only one so far had 65 people and lasted 6 weeks.
• Results from registered trials. Three are listed as completed without posted results, and a trial comparing coffee with a hibiscus drink is not yet recruiting.
• Trials in people with diagnosed hypertension that meet the Cochrane criteria, which would test whether the pooled drop survives a stricter reading.
• Any data on pregnancy, and on people taking blood pressure drugs or warfarin.

What hibiscus tea contains and the rest of its evidence is on the hibiscus tea page.

Sources

1. ev-hibbp-01 · Meta-analysis or systematic review · systematic review and meta-analysis of RCTs · n = 819
   Hibiscus resulted in a significant reduction of SBP (−7.10 mmHg; 95%CI, −13.00, −1.20; I2 = 95%; P = 0.02). The results for DBP favored hibiscus but did not reach statistical significance (−3.26 mmHg; 95%CI, −7.05, 0.52; I2 = 94%; P = 0.09).
   
   Who: adults in randomized trials comparing hibiscus with another tea, placebo or a prescribed diet; 415 hibiscus and 404 control participants across blood pressure outcomes
   Effect: SBP -7.10 mmHg (95% CI -13.00 to -1.20; I2 95%); DBP -3.26 mmHg (-7.05 to 0.52), not significant
   Certainty: 17 RCTs overall, 12 with blood pressure data; heterogeneity 94-95%; allocation concealment described in 6 studies only.
   Nutrition Reviews, 2022: A systematic review and meta-analysis of the effects of Hibiscus sabdariffa on blood pressure and cardiometabolic markers · checked 2026-10-06 · we read the fulltext
2. ev-hibbp-02 · Meta-analysis or systematic review · systematic review and meta-analysis of RCTs, placebo subgroup · n = —
   There was a significant effect of hibiscus, compared with placebo, on SBP (−10.05 mmHg; 95%CI, −17.58, −2.51; I2 = 81%; P = 0.009).
   
   Who: adults in placebo-controlled randomized trials of hibiscus
   Effect: vs placebo: SBP -10.05 mmHg (95% CI -17.58 to -2.51; I2 81%); DBP -5.60 mmHg (-13.05 to 1.85), not significant
   Certainty: Subgroup of a small set of trials; wide intervals.
   Nutrition Reviews, 2022: A systematic review and meta-analysis of the effects of Hibiscus sabdariffa on blood pressure and cardiometabolic markers · checked 2026-10-06 · we read the fulltext
3. ev-hibbp-03 · Meta-analysis or systematic review · systematic review and meta-analysis of RCTs, dose and duration subgroups · n = —
   Within the dose-response subgroup, ingestion of hibiscus with a dose ≤1 g/day was not significant for either SBP (P = 0.96) or DBP (P = 0.63).
   
   Who: adults in randomized trials of hibiscus, split by dose and duration
   Effect: dose 1 g/day or less: no SBP (P=0.96) or DBP (P=0.63) effect
   Certainty: The authors say the small number of trials does not allow a dose or duration to be proposed.
   Nutrition Reviews, 2022: A systematic review and meta-analysis of the effects of Hibiscus sabdariffa on blood pressure and cardiometabolic markers · checked 2026-10-06 · we read the fulltext
4. ev-hibbp-04 · Meta-analysis or systematic review · systematic review and meta-analysis of RCTs, active-comparator subgroup · n = 4 trials
   Hibiscus had similar BP-lowering effects as pharmaceutical intervention, with a nonsignificant difference observed between the 2 treatments: SBP (2.13 mmHg; 95%CI, −2.81, 7.06; I2 = 91%; P = 0.40) and DBP (1.10 mmHg; 95%CI, −1.55, 3.74; I2 = 91%; P = 0.42).
   
   Who: adults with hypertension in randomized trials comparing hibiscus with captopril, lisinopril, ramipril or hydrochlorothiazide
   Effect: hibiscus vs drug: SBP 2.13 mmHg (95% CI -2.81 to 7.06); DBP 1.10 mmHg (-1.55 to 3.74); I2 91%
   Certainty: No significant difference is not proof of equivalence; 250 mg hibiscus was weaker than 10 mg lisinopril in one trial.
   Nutrition Reviews, 2022: A systematic review and meta-analysis of the effects of Hibiscus sabdariffa on blood pressure and cardiometabolic markers · checked 2026-10-06 · we read the fulltext
5. ev-hibbp-05 · Meta-analysis or systematic review · systematic review and fixed-effect meta-analysis of RCTs · n = 390
   Fixed-effect meta-regression indicated a significant effect of H. sabdariffa supplementation in lowering both SBP (weighed mean difference -7.58 mmHg, 95% confidence interval -9.69 to -5.46, P < 0.00001) and DBP (weighed mean difference -3.53 mmHg, 95% confidence interval -5.16 to -1.89, P < 0.0001).
   
   Who: 390 participants randomized in 5 RCTs (7 treatment arms), searched to July 2014
   Effect: SBP WMD -7.58 mmHg (95% CI -9.69 to -5.46); DBP WMD -3.53 mmHg (-5.16 to -1.89); effect larger with higher baseline BP
   Certainty: Fixed-effect model on 5 small trials; outside the local corpus snapshot.
   J Hypertens, 2015: Effect of sour tea (Hibiscus sabdariffa L.) on arterial hypertension, a systematic review and meta-analysis of randomized controlled trials · checked 2026-10-06 · we read the abstract
6. ev-hibbp-06 · Meta-analysis or systematic review · systematic review and meta-analysis of RCTs · n = 1205
   Hibiscus sabdariffa significantly reduced both SBP and DBP compared with placebo (mean difference -6.67, P = 0.004 and -4.35 mm Hg, P = 0.02).
   
   Who: patients with mild-to-moderate hypertension or hypertension with metabolic syndrome in 13 RCTs
   Effect: vs placebo: SBP MD -6.67 mmHg (P=0.004), DBP MD -4.35 mmHg (P=0.02)
   Certainty: Confidence intervals not given in the abstract; outside the local corpus snapshot.
   J Cardiovasc Pharmacol, 2022: Efficacy of Hibiscus sabdariffa on reducing blood pressure in patients with mild-to-moderate hypertension · checked 2026-10-06 · we read the abstract
7. ev-hibbp-07 · Meta-analysis or systematic review · Cochrane systematic review of randomized trials · n = 52
   The evidence is currently insufficient to determine the effectiveness of Roselle compared to placebo for controlling or lowering blood pressure in people with hypertension.
   
   Who: adults with primary hypertension; one included RCT of 60 people with type 2 diabetes, roselle extract capsules for 8 weeks
   Effect: SBP MD 1.65 mmHg (95% CI -7.89 to 11.19); DBP MD 4.60 mmHg (-1.38 to 10.58); very low certainty
   Certainty: Very low certainty; strict criteria (placebo or no treatment, diagnosed hypertension) exclude most trials pooled in other meta-analyses.
   Cochrane Database Syst Rev, 2021: Roselle for hypertension in adults · checked 2026-10-06 · we read the abstract
8. ev-hibbp-08 · Meta-analysis or systematic review · umbrella review with updated dose-response meta-analysis of RCTs · n = 1797
   Data from 26 randomized controlled trials involving 1797 participants revealed that HS dose-dependently reduced systolic and diastolic BP compared to placebo and other teas.
   
   Who: participants in 26 randomized controlled trials, meta-analyses searched to May 2024
   Effect: dose-dependent SBP and DBP reduction vs placebo and other teas
   Certainty: GRADE and ICEMAN used; numbers per outcome not in the abstract; outside the local corpus snapshot.
   Complement Ther Med, 2025: Efficacy and safety of Hibiscus sabdariffa in cardiometabolic health, an overview of reviews and updated dose-response meta-analysis · checked 2026-10-06 · we read the abstract
9. ev-hibbp-09 · Meta-analysis or systematic review · umbrella review with updated meta-analysis of RCTs · n = 1797
   A minor, clinically insignificant increase in aspartate aminotransferase was observed without elevating adverse event risks.
   
   Who: participants in randomized trials of hibiscus
   Effect: minor, clinically insignificant AST increase; adverse event risk not raised; long-term therapeutic dosing safety needs monitoring
   Certainty: Trials were short; long-term safety not established.
   Complement Ther Med, 2025: Efficacy and safety of Hibiscus sabdariffa in cardiometabolic health, an overview of reviews and updated dose-response meta-analysis · checked 2026-10-06 · we read the abstract
10. ev-hibbp-10 · Meta-analysis or systematic review · systematic review and meta-analysis of RCTs, adverse event reporting · n = 17 trials
    In the studies included in this meta-analysis, authors of 1 study reported mild gastrointestinal symptoms using 1 g of hibiscus extract after the first week of supplementation; however, these symptoms subsided within 1 week.
    
    Who: participants in 17 randomized trials of hibiscus, doses 15 mg to 9-10 g a day for 15 to 90 days
    Effect: mild gastrointestinal symptoms in 1 study; no other adverse effects reported
    Certainty: Trials up to 90 days; adverse events poorly reported in small trials.
    Nutrition Reviews, 2022: A systematic review and meta-analysis of the effects of Hibiscus sabdariffa on blood pressure and cardiometabolic markers · checked 2026-10-06 · we read the fulltext
11. ev-hibbp-11 · Randomized controlled trial(s) · randomized double-blind placebo-controlled trial, 6 weeks · n = 65
    At 6 wk, hibiscus tea lowered systolic BP (SBP) compared with placebo (-7.2 +/- 11.4 vs. -1.3 +/- 10.0 mm Hg; P = 0.030).
    
    Who: 65 pre- and mildly hypertensive adults aged 30 to 70 not taking blood pressure medication
    Effect: SBP -7.2 vs -1.3 mmHg (P=0.030); DBP -3.1 vs -0.5 mmHg (P=0.160)
    Certainty: Three 240-mL servings of brewed tea a day; small trial; larger effect with higher baseline SBP.
    J Nutr, 2010 · checked 2026-10-06 · we read the abstract
12. ev-hibbp-12 · Randomized controlled trial(s) · randomized clinical trial, active comparator, 4 weeks · n = 100
    The systolic pressure of both groups statistically decreased at the end of the study; it decreased from 123.1 ± 15.5 to 116.8 ± 16.3 mmHg in the ST and from 119.4 ± 15.1 to 114.8 ± 15.9 mmHg in the GT.
    
    Who: 100 mildly hypertensive patients with type 2 diabetes
    Effect: SBP 123.1 to 116.8 mmHg on sour tea vs 119.4 to 114.8 on green tea; no placebo arm
    Certainty: No placebo; within-group changes only.
    J Diet Suppl, 2013 · checked 2026-10-06 · we read the abstract
13. ev-hibbp-13 · Laboratory or animal data · case report · n = 1
    We describe the case of a 59-year-old woman with a mechanical mitral valve receiving chronic warfarin therapy who developed a markedly elevated international normalized ratio (INR) after recently consuming hibiscus tea.
    
    Who: one 59-year-old woman with a mechanical mitral valve on chronic warfarin
    Effect: markedly elevated INR; normalized after stopping hibiscus, holding warfarin and giving vitamin K
    Certainty: Single case; causality possible, not proven.
    Cureus, 2026 · checked 2026-10-06 · we read the abstract