She will tell Heng Yue that Stardust is essentially crystalized cosmic mana, created by a process unique to this realm, but she's not entirely certain how that process works, or why it only happens during Tanabata season. That being said, because of what it is, it can be used to increase the potency of various medicines. Psychoactives, sedatives, muscle relaxers, other medicines that interact with the nervous system in particular.

Her own research is determining its properties in temporal medicine, whether the energy of stars can reverse the conditions of a given physical body. Essentially "rewinding" wounds or other deterioration.