To obtain a disinfectant, sterilizer extracted from plant Alpinia speciosa and harmless to human bodies.

When roots, stems and leaves of Alpinia speciosa are cut and put into a pan, added with a suitable amount of water and boiled, fragrant odors are evaporated and hardly remain, thus the fragrant odors are confirmed to be extracted by a distillation device. The extracted liquid does not stink and decay any more, so the extract is brought to be an additive for disinfection and sterilization.