The invention provides a vegetal black hair dyeing agent and a hair dyeing method, in which plant extracts of eucalyptus leaves and teak leaves are used as main materials. The vegetal black hair dyeing agent is divided into a first agent and a second agent. The plant extract in the first agent is used firstly in a warm environment so as to penetrate into hair fibers, and then it complexes with ferrous ions of the second agent to form a macromolecular insoluble black substance for being fixed to the hair. The first agent may further be used in combination with Indigo plants or tea plant extracts to achieve a hair dyeing color of dark black. Without using any chemical solvent, penetrating agent and surfactant that is harmful to human body, the invention is advantageous in having a simple and safe formula and providing an improved dyeing effect.一種植物性黑色染髮劑及染髮方法，是採用桉樹葉及柚木葉之植物萃取物為主要原料，此植物性黑色染髮劑分為第一劑和第二劑，先利用第一劑中的植物萃取物於溫熱環境下滲入頭髮纖維中，再與第二劑中的亞鐵離子絡合形成大分子不溶性黑色物質而固著於頭髮上；其中，第一劑進一步可搭配印地科植物或茶葉植物萃取物共同使用，而染得深黑色之髮色。本發明並未使用化學溶劑、滲透劑及表面活性劑等對人體有害之物質，配方簡單、安全，且染色效果佳。
