Hibiscus (Hibiscus spp.) Dosing and Safety

safety

Allergies

Avoid in individuals with a known allergy or hypersensitivity to hibiscus, its constituents, or members of the Malvaceae family. Reported allergy symptoms include skin rash and hives.

Side Effects and Warnings

There is limited reported safety data about hibiscus, although it is popularly used as a tea.
Although not well studied in humans, excessive doses of hibiscus for relatively long periods may have antifertility effects. One study found that hibiscus tea contained polycyclic aromatic hydrocarbons (PAHs). PAHs have been associated with birth defects and cancer. The sources of PAHs in food are predominantly from environmental pollution and food processing. Use cautiously in patients with hypertension or hypotension (high or low blood pressure), as hibiscus may lower blood pressure.

Pregnancy and Breastfeeding

Hibiscus is not recommended in pregnant or breastfeeding women due to a lack of available scientific evidence. However, Hibiscus tiliaceus has been used throughout the Vanuatu archipelago to speed childbirth. In theory, excessive doses of hibiscus for relatively long periods may have antifertility activity, and caution is advised.

dosing

Adults (18 years and older)

There is no proven effective dose for hibiscus, although an herbal infusion prepared with 10 grams of dry calyx from Hibiscus sabdariffa with 0.51 water (9.6mg anthocyanins content), daily before breakfast showed similar results as captopril 25 milligrams twice a day for four weeks.

Children (younger than 18 years)

There is no proven safe or effective dose for hibiscus in children.

interactions

Interactions with Drugs

Although not well studied in humans, hibiscus may have anticancer effects. Thus, caution is advised when taking hibiscus with other anticancer agents.
Extracts of hibiscus may lower the systolic and diastolic pressure. Patients taking blood pressure lowering agents should use hibiscus cautiously due to additive effects. Consult with a qualified healthcare professional, including a pharmacist, to check for interactions.
Zobo drink (made from hibiscus) may change the way certain anti-inflammatory agents, such as acetaminophen, are processed in the body. Caution is advised when taking anti-inflammatory agents and hibiscus within a two-hour period of one another.
Karkadi beverage (Hibiscus sabdarifa) may reduce antimalarial (quinine, chloroquine) efficacy.
Antiviral effects have been observed in preliminary laboratory study. In theory, hibiscus taken with other antiviral agents may have additive effects.
Hibiscus rosa-sinensis may have estrogenic activity, although the clinical significance is unclear. Use hibiscus cautiously in patients taking hormone altering agents, such as hormone replacement therapy or birth control pills.

Interactions with Herbs and Dietary Supplements

Although not well studied in humans, hibiscus may have anticancer effects. Thus, caution is advised when taking hibiscus with other anticancer agents.
Extracts of hibiscus may lower the systolic and diastolic pressure. Patients taking herbs that lower blood pressure should use hibiscus cautiously due to additive effects. Consult with a qualified healthcare professional, including a pharmacist, to check for interactions.
In theory, Karkadi beverage (Hibiscus sabdarifa) may reduce the efficacy of antimalarial herbs and supplements.
Antiviral effects have been observed in preliminary laboratory study. In theory, hibiscus taken with other herbs with antiviral activity may have additive effects.
Hibiscus rosa-sinensis may have estrogenic activity, although the clinical significance is unclear. Use hibiscus cautiously in patients taking hormone altering herbs or supplements.