High blood pressure. Most early research shows that drinking hibiscus tea for 2-6 weeks decreases blood pressure by a small amount in people with normal or high blood pressure. Some early research shows that drinking hibiscus tea might be as effective as the prescription drugs captopril and more effective than the drug hydrochlorothiazide for reducing blood pressure in people with slightly high blood pressure.
https://www.webmd.com/vitamins/ai/ingredientmono-211/hibiscus
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3593772/
https://www.webmd.com/vitamins/ai/ingredientmono-211/hibiscus
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3593772/