An agent for preventing and treating alopecia by a biological ferment comprises a biological enzyme ferment and a traditional Chinese medicine additive. The weight ratio of the biological enzyme ferment to the traditional Chinese medicine additive is 9:1. The biological enzyme ferment is fermented from the following materials: water, brown sugar, Poria, Rohdea japonica, Fructus Chaenomelis, Flos Lonicerae, Camellia oleifera seed, Folium Perillae, Fructus Citri Sarcodactylis, and Citrus limon. The traditional Chinese medicine additive is prepared from the following raw materials: Radix Polygoni Multiflori, germanite, Fructus Schisandrae, Rhizoma Polygoni Cuspidati, Endothelium Corneum Gigeriae Galli, Fructus Lycii, and Rhizoma Dioscoreae. The method for preparing an agent for preventing and treating alopecia comprises: preparing the biological enzyme ferment removing impurities to obtain a clarified liquid adding a natural stabilizer eluting a filtrate and adding the traditional Chinese medicine additive. The agent for preventing and treating alopecia has a significant prevention and treatment effect on seborrheic alopecia and psychogenic hair loss, and has no toxic and side effects.Linvention concerne un agent pour prévenir et traiter lalopécie par un ferment biologique comprenant un ferment enzymatique biologique et un additif de médecine chinoise traditionnelle. Le rapport pondéral du ferment enzymatique biologique sur ladditif de médecine chinoise traditionnelle est de 9:1. Le ferment enzymatique biologique est fermenté à partir des matériaux suivants : eau, sucre brun, Poria, Rohdea japonica, Fructus Chaenomelis, Flos Lonicerae, grains de Camellia oleifera, Folium Perillae, Fructus Citri Sarcodactylis, et Citrus limon (Le citronnier). Ladditif de médecine chinoise traditionnelle est préparé à partir des matières premières suivantes : Radix Polygoni Multiflori, germanite, Fructus Schisandrae, Rhizoma Polygoni Cuspidati, Endothelium Corneum Gigeriae Galli, Fructus
