Tree Peony (Paeonia suffruticosa), particularly its root bark (known as "Moutan Cortex"), has a long history of use in traditional Chinese medicine (TCM) for skin conditions, including psoriasis. In recent years, scientific studies have begun to explore its potential therapeutic effects on psoriasis. Laboratory and animal studies suggest that bioactive compounds in Tree Peony, such as paeonol and paeonoside, possess anti-inflammatory, immunomodulatory, and antioxidant properties relevant to the pathogenesis of psoriasis. These compounds have been shown to inhibit the release of pro-inflammatory cytokines (such as TNF-α, IL-6, and IL-17) and reduce keratinocyte proliferation in cell-based models. Some small animal studies have demonstrated improvement in psoriasiform dermatitis with Tree Peony extracts. However, clinical evidence in humans is limited; only a few small-scale clinical trials have tested traditional Chinese herbal formulas containing Tree Peony, and these studies often include multiple herbs, making it difficult to isolate the effect of Tree Peony itself. While preclinical data are promising, high-quality randomized controlled trials in humans are lacking. Thus, Tree Peony's use in psoriasis is scientifically plausible but not conclusively validated, warranting a moderate evidence rating.