Black tea helps relax blood vessels, due to its flavonoid content, helping to prevent oxidation of good cholesterol. Its consumption is not recommended for people with high blood pressure due to its theine content. Recommended method of preparation for infusions: Pour the contents of a tablespoon into boiling water and remove from heat. Cover the container and let it steep for 8 to 10 minutes. If using roots, bark, or seeds, simmer for 2 to 4 minutes. Strain and sweeten to taste.