Can the medicine st johns wort work?

Depends: At johns wort is not a medicine, it is a supplement. It has shown to improve depression in people with mild depression. Please see a psychiatrist for further evaluation of your depression and appropriate treatment.

St. John's Wort: St. John's wort is a botanical medicine which has been used extensively in germany and other european countries for depression and anxiety, and studied & used in the us as well. Multiple studies and meta-analyses indicate it's as effective as tricyclic antidepressants and serotonin reuptake inhibitors in the short-term management of mild-moderate depression. However, not for more severe cases.