The invention discloses a drug for treating multiple common skin diseases. Raw materials preparing the drug comprise rhizoma smilacis glabrae, veratrilla baillonii franch, honeysuckle, dandelion, cortex dictamni, cortex moutan, radix isatidis, fructus kochiae, common cnidium fruit, Chinese trumpetcreeper flower, fructus xanthii, herba scutellariae barbatae, common andrographis herb, tribulus terrestris, motherwort herb, hedyotis diffusa, herba siegesbeckiae, radix trichosanthis, wild chrysanthemum, nidus vespae, fructus forsythiae, cape jasmine fruit, cortex phellodendri, rhizoma coptidis, mint, agastache rugosus, purple perilla, radix angelicae, pericarpium zanthoxyli, bombyx batryticatus, periostracum cicada, snake slough, zaocys dhumnade, silkworm excrement, realgar, borneol, camphor, sulfur, calamine, borax, alumen, colophonium, rheum officinale, raw licorice root, herba schizonepetae, radix saposhnikoviae, and shrubalthea bark. The drug has the efficacies of clearing heat and detoxifying, eliminating dampness, relieving itching, eliminating swelling, moisturizing skin, killing inspects and the like, has significant curative effects on some common skin diseases, such as dermatitis, urticaria, cutaneous pruritus and scabies, and has no side effect.