Schizonepeta spike,the spike of the herb,also called Jing jie sui.It has a stronger therapeutic effect than the leaves and stem.

The spike of Schizonepeta is the preferred portion. Schizonepeta was first described in the Advanced Textbook on Traditional Chinese Medicine and Pharmacology (ca. 100 A.D.) as acrid and warm, mainly used to treat cold and heat disorders, fistulas, and scrofulous swellings.

The main active constituents of schizonepeta are understood to be the essential oils, which comprise about 1.8% of the tops and are dominated by the monoterpene aldehydes menthone and pulegone.  The physiological properties of menthone are essentially the same as those of menthol, namely dilating peripheral blood vessels, alleviating pain, and inhibiting bacteria. The monoterpenes in both mentha and schizonepeta may also have some ability to treat pruritis associated with allergy-caused rashes; pulegone has antiinflammatory and antipyretic effects.