Salt tablet
A handful of salt tablets
A salt tablet was a pill composed of salt, used to restore one's salt levels after heat exposure.
In 2265, "Nancy Crater" asked Robert Crater if he had requested more salt tablets from the USS Enterprise , after which he assured her he would.
Later, while investigating the deaths of individuals whose bodies' salt content had been depleted, James T. Kirk and Leonard McCoy recalled "Nancy" and Robert's insistence on more salt. Upon questioning the professor, Robert countered by asking if the doctor knew why they required salt on a hot planet like M-113.
Ultimately, the salt vampire was lured into revealing its need for salt and its true form by Kirk, who used the tablets as bait. (TOS: "The Man Trap")