St. John’s wort‚ which is also known as Hypericum perforatum‚ has been used in traditional medicine since the days of the ancient Greeks. It may have a mild sedative effect‚ and might work to alleviate mild feelings of sadness or anxiety. This herb‚ which is found in Seroyal's St. Johnswort Plus‚ contains chemicals that may affect the reabsorption of certain neurotransmitters. As a result‚ chemicals such as serotonin may be more available for your body to use in order to promote calm.