From WebMD :
Skullcap is a plant. The above ground parts are used to make medicine.
Skullcap is used for many conditions, but so far, there isn’t enough scientific evidence to determine whether or not it is effective for any of them.
Skullcap is used for trouble sleeping (insomnia), anxiety, stroke, and paralysis caused by stroke. It is also used for fever, high cholesterol, “hardening of the arteries” (atherosclerosis), rabies, epilepsy, nervous tension, allergies, skin infections,inflammation, and spasms.
Skullcap products are not always what the labels claim. The plants germander and teucrium are often unwanted and unlabeled ingredients in skullcap products. Secondly, you may think you are buying Scuttelaria lateriflora, the species of skullcap that has been studied for medicinal use, but the product may contain a different species of skullcap instead. The most often substituted species are Western Skullcap (Scuttelaria canescens), Southern Skullcap (Scutellaria cordifolia), or Marsh Skullcap (Scutellaria galericulatum). These species contain different chemicals, so they are not considered interchangeable.
How does it work?
The chemicals in skullcap might work by preventing swelling (inflammation). Other chemicals in skullcap are thought to cause sedation (drowsiness).
Disclaimer – No medical claims are being made in regards to any of the products or their efficiency dealing with any health concerns or benefits. Act responsibly and seek qualified medical advice before using any of the products especially when pregnant, nursing or taking medications.