Hibiscus
In short
Summary of findings for quick reference
Hibiscus calyces connect several tea traditions: karkade in Sudan and Egypt, bissap in West Africa, agua de Jamaica in Mexico and sorrel in the Caribbean. Trade also brought them to Europe. This living beverage culture is widely documented, although the beginnings of individual uses cannot always be dated securely.
A 2015 meta-analysis by Serban and colleagues found short-term reductions in systolic and diastolic blood pressure, although studies were small and short and preparations and doses varied. A 2021 Cochrane review with narrower eligibility criteria for people with hypertension judged the evidence insufficient. Hibiscus tea should not replace blood pressure treatment.
Hibiscus is mainly familiar as a caffeine-free tea. There is no EMA monograph; the European Pharmacopoeia entry sets quality standards for the calyces. EFSA did not substantiate the diuretic-function and bowel-function health claims in 2009. Discuss regular consumption with your doctor if you take blood pressure medicines. Use Hibiscus sabdariffa for tea, not ornamental Hibiscus rosa-sinensis.
Clinical evidence ↔ Historical significanceWe display two separate evidence categories: clinical evidence from modern trials and historical significance from documented healing tradition. Both are valuable, but they answer different questions.Read more
In every encyclopedia entry we evaluate two distinct categories of evidence. Clinical evidence as used in trials meets a narrower but scientifically essential bar. At the same time, the hundreds of thousands of plant species worldwide have only partially been captured and tested in modern studies.
Alongside the trial picture our researchers compile a comprehensive overview of where and since when a plant has been used across different traditions of natural medicine. When a plant has been used as a medicinal plant in many cultures across many generations, that historical significance deserves to be visible too.
Our position: a truly informative overview emerges only when both categories sit side by side. We communicate transparently what counts as what.
Overview
Hibiscus (Hibiscus sabdariffa), also called roselle, is a tropical shrub in the mallow family (Malvaceae). Tea is made from the fleshy, usually deep red calyces and epicalyces surrounding the seed capsule after flowering. Anthocyanins provide the ruby colour, while organic acids including citric, malic and hibiscic acid contribute the tart flavour. There is no EMA monograph for Hibiscus sabdariffa. The European Pharmacopoeia Roselle entry is a quality standard. The Egyptian Drug Authority (2023) lists the calyx as a traditional hypertension adjuvant based on longstanding use.
The drink is known as karkade in Sudan and Egypt, bissap in West Africa and agua de Jamaica in Mexico. Depending on the region it is served hot or chilled, often sweetened. Hibiscus is also a caffeine-free ingredient in teas and summer drinks in Europe. Some clinical trials, including those pooled by Serban and colleagues (2015), found short-term blood pressure changes, but the findings do not establish hibiscus tea as a treatment.
History
Hibiscus sabdariffa is native to tropical Africa and has been cultivated for the fleshy red calyces for at least several centuries. The plant travelled with trade routes through North Africa, the Arabian peninsula, the Caribbean, Mexico, and South-East Asia. In each of these regions a local drink emerged: Karkadeh in Sudan and Egypt, Bissap in Senegal and West Africa, agua de jamaica in Mexico, sorrel in the Caribbean. All of them work the same way, an infusion of fresh or dried red calyces, served hot or chilled, often sweetened.
In Europe hibiscus spread mainly through the tea trade. The ruby-red infusion is served hot or chilled. There is no EMA herbal monograph for hibiscus. The European Pharmacopoeia includes a Roselle quality monograph for dried calyces and epicalyces, and the Egyptian Drug Authority (2023) lists the calyx as a traditional adjuvant in the management of hypertension.
Mechanism
Anthocyanins, including delphinidin and cyanidin glycosides, are prominent in research on hibiscus calyces. They provide the red colour and show antioxidant properties in laboratory studies. Organic acids such as citric, malic and hibiscic acid contribute the tart taste. Laboratory findings alone do not establish health benefits from a cup of tea.
It is not fully established which constituents explain effects observed in humans. Clinical research includes both tea and extracts: McKay and colleagues, for example, studied three servings of brewed hibiscus tea daily. Results do not automatically apply to every tea blend or extract.
Research focuses mainly on constituents and possible blood pressure effects. In a placebo-controlled trial by McKay and colleagues (2010), 65 adults not taking blood pressure medicines drank three 240-mL servings of tea daily for six weeks; systolic but not diastolic blood pressure improved versus placebo. Serban and colleagues (2015) pooled five trials involving 390 participants and found reductions in both measures. Hopkins and colleagues (2013) reviewed animal and human research on hypertension and hyperlipidaemia.
The findings remain uncertain. For its question about effectiveness in hypertension, the 2021 Cochrane review included only one trial with 60 participants and found insufficient reliable evidence. The Egyptian Drug Authority (2023) lists hibiscus as a traditional hypertension adjuvant based on longstanding use, which is distinct from demonstrated clinical efficacy. The European Pharmacopoeia Roselle monograph sets quality standards; there is no EMA monograph.
Usage
Forms and preparation
For hot tea, pour 240 mL boiling water over about 1.5 g dried hibiscus calyces. Steep for five to ten minutes, then strain, also following the package instructions. The tea becomes deep red and tastes tart. Add a little honey if you want sweetness, or a lemon slice for flavour. For a chilled hibiscus drink, brew the tea with boiling water first. Cool the strained infusion promptly, refrigerate and serve over ice. Ordinary dried calyces should not simply be soaked in cold or lukewarm water. Mint, ginger or a squeeze of lime work well with it.
Dosage
For use as a drink, follow the package preparation instructions. For traditional medicinal adjunctive use in hypertension, the 2023 EDA monograph specifies tea made from 1.25 to 1.5 g dried calyces in 240 mL water, up to three times daily for up to six weeks. This is not a general drinking recommendation or an EMA authorisation. Discuss targeted blood pressure use with your doctor. Studies have tested both tea and extracts. In the McKay trial (2010), participants drank three 240-mL servings of brewed tea daily for six weeks and were not taking blood pressure medicines. That study regimen is neither a general recommendation nor transferable to arbitrary extracts; composition and product instructions matter.
Safety
Look-alikes
Similar plants and look-alikes
Hibiscus rosa-sinensis (ornamental hibiscus)
Ornamental hibiscus (Hibiscus rosa-sinensis) is the species widely grown in central Europe as an indoor or patio plant, with large single flowers in many colours. It belongs to the same genus but does not produce the fleshy red calyces that Karkadeh and agua de jamaica are made from. Use food-grade Hibiscus sabdariffa for Karkadeh; ornamental plants are not a substitute.
FAQs
Karkadeh, Bissap, agua de jamaica, Roselle, are they all the same?
Yes, they refer to the same plant, Hibiscus sabdariffa, and drinks made from its calyces. Karkade is used in Sudan and Egypt, bissap in West Africa, agua de Jamaica in Mexico and sorrel in the Caribbean. Roselle is the English name of the plant. The use of fresh or dried calyces and the degree of sweetening vary by region.
Better hot or cold?
Hibiscus tea can be served hot or chilled. Even for a cold drink, pour boiling water over dried calyces and steep for at least five minutes, following the package instructions. For iced tea, strain, cool promptly and refrigerate before serving over ice.
Can I drink hibiscus if I take blood pressure medication?
Talk to your doctor before drinking hibiscus regularly. It may add to the effect of blood-pressure-lowering medicines, but the size of this interaction is not well established. Watch for unusually low readings or dizziness and do not change prescribed medicines on your own.
Is hibiscus safe in pregnancy?
Reliable safety data in pregnancy and breastfeeding are lacking, so the Egyptian Drug Authority does not recommend medicinal use. The evidence does not establish a safe allowance such as one or two cups per week. Discuss regular hibiscus tea consumption or extracts with your doctor or midwife.
8 sources.
- Diane L. McKay, C.-Y. Oliver Chen, Edward Saltzman, Jeffrey B. Blumberg. Hibiscus sabdariffa L. tea (tisane) lowers blood pressure in prehypertensive and mildly hypertensive adults. 2010. doi:10.3945/jn.109.115097
- Corina Serban, Amirhossein Sahebkar, Sorin Ursoniu, Florina Andrica, Maciej Banach. Effect of sour tea (Hibiscus sabdariffa L.) on arterial hypertension: a systematic review and meta-analysis of randomized controlled trials. 2015. doi:10.1097/HJH.0000000000000585
- Porjai Pattanittum, Chetta Ngamjarus, Fonthip Buttramee, Charoonsak Somboonporn. Roselle for hypertension in adults. 2021. doi:10.1002/14651858.CD007894.pub3
- Allison L. Hopkins, Marnie G. Lamm, Janet L. Funk, Cheryl Ritenbaugh. Hibiscus sabdariffa L. in the treatment of hypertension and hyperlipidemia: a comprehensive review of animal and human studies. 2013. doi:10.1016/j.fitote.2013.01.003
- J. A. Kolawole, A. Maduenyi. Effect of zobo drink (Hibiscus sabdariffa water extract) on the pharmacokinetics of acetaminophen in human volunteers. 2004. doi:10.1007/BF03190570
- Egyptian Drug Authority. Egyptian Herbal Monograph: Hibiscus sabdariffa L. (Karkade). 2023. Source
- EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific opinion on health claims related to Hibiscus sabdariffa L. and improvement of diuretic function and bowel motor function. 2009. doi:10.2903/j.efsa.2009.1293
- Bundesinstitut für Risikobewertung (BfR). Kräutertees unbedingt mit kochendem Wasser aufgießen!. 2005. Source
Legal notice: The depiction of historical significance and traditional use is context within our encyclopedia and not a health claim for any product, not a treatment promise, and not a substitute for medical advice. What may be stated on product labels, product pages, or in advertising is governed by the applicable legal requirements.