Though ketovatru several studies proved the tea was effective, a huge review study proved that those effects were not significant on blood-lipid levels.Another test-tube study found that hibiscus tea is very effective against the anxieties of bird flu. Nevertheless, no study proves that you can fight flu viruses when you take hibiscus tea.Further, many studies prove that hibiscus tea has positive impacts on high velofel blood pressure. While most of those studies were low quality, drinking this tea might reduce high blood pressure.