Nail involvement is highly prevalent in psoriasis but often overlooked by physicians, despite the significant patient burden due to pain, psychological stress, and impairment of manual dexterity. Notwithstanding many recent advances in cutaneous psoriasis treatment, options for nail psoriasis remain far more limited in scope and efficacy. Herein, we report a novel finding that patients with moderate to severe psoriatic nails responded well to treatment with indigo naturalis oil extract drops. To our knowledge, this is the first report on the ability of traditional Chinese medicine to treat psoriatic nail disease.