This study reviewed the biological action of key herbs and evaluated systematically the efficacy and safety of oral Gentiana formula for herpes zoster (HZ). Experimental studies relevant to HZ were identified in PubMed. Randomized controlled trials using Gentiana formula for HZ were identified from nine English and Chinese databases. The primary outcome was evaluation of pain. Potential risk of bias was assessed. Meta-analysis was conducted using mean difference or risk ratio with 95% confidence intervals. Key herbs Gentiana scabra Bunge, Gentiana triflora Pall, Scutellaria baicalensis Georgi, and Gardenia jasminoides Ellis have shown antiinflammatory actions through inhibition of inflammatory cytokines and pro-inflammatory enzymes. Twenty-six clinical studies, involving 2955 participants, were included. Modified Gentiana formula resolved pain earlier than pharmacotherapy when used alone or combined with topical Chinese herbal medicine. Incidence of postherpetic neuralgia was lower (risk ratio 0.14, 95% confidence interval 0.03 to 0.74) with modified Gentiana formula plus topical Chinese herbal medicine. Mild adverse events were reported. Antiinflammatory actions of key herbs of Gentiana formula may explain clinical benefit in hastening pain relief and decreasing postherpetic neuralgia. Few adverse events were reported. Findings were limited by study quality and diversity in intervention and comparator dosage. Copyright (C) 2017 John Wiley & Sons, Ltd.