Results Thirty-two studies met the inclusion criteria. Clinical studies were divided into three categories: survey studies (n=11), safety studies (n= 8), and efficacy studies (n= 13). Six studies were randomized controlled trials. The most common herbs studied were St. John’s wort (Hypericum perforatum L.) (n=3), garlic (Allium sativum L.) extract (n=2), and senna (Cassia senna L.) (n=2). Studi...
