Milk thistle is an herb with history. For more than 2,000 years, humans have turned to milk thistle (Silybum marianum) for its healing effects, with its first use dating back to ancient Greece, where it was reportedly used as a liver tonic and as a treatment for snake bites and mushroom poisoning. John Gerard, an English herbalist who lived during the Renaissance, noted that milk thistle was “the best remedy against melancholy diseases.”¹ In other words, depression.