Thymol, white Crystal or crystalline powder, and carvacrol are isomers having been found in thyme got its name. With pleasant aromatic odor. Soluble in organic solvents such as ethanol, slightly soluble in water and Glycerin. Have a strong corrosive effect, is a strong preservative, used to control the number of Varroa mite on honey bees, book binding and add III fluorine chlorine to ethylene as an anesthetic.

The bactericidal effect of thymol is stronger than that of phenol, and the toxicity is low. It has disinfection and fungicidal effect on oral and pharynx mucosa, as well as antisepsis and local anesthesia effect on dental caries.Can promote the movement of tracheal cilia, conducive to the secretion of tracheal mucus, easy to play the role of expectoration, plus sterilization, so can be used for the treatment of tracheitis, pertussis.
Thymol has been used in alcohol solutions and in dusting powders for the treatment of tinea or ringworm infections, and was used in the United States to treat hookworm infections. People of the Middle East continue to use za'atar, a delicacy made with large amounts of thyme, to reduce and eliminate internal parasites. It is also used as a preservative in halothane, an anaesthetic, and as an antiseptic in mouthwash. When used to reduce plaque and gingivitis, thymol has been found to be more effective when used in combination with chlorhexidine than when used purely by itself. Thymol is also the active antiseptic ingredient in some toothpastes, such as Johnson & Johnson's Euthymol. Thymol has been used to successfully control varroa mites and prevent fermentation and the growth of mold in bee colonies. Thymol is also used as a rapidly degrading, non-persisting pesticide. Thymol can also be used as a medical disinfectant and general purpose disinfectant.