What does alterative mean?
The definition of alterative
Al”ter*a*tive, a.
Etym: [L. alterativus: cf. F. altératif.]

Causing ateration. Specifically:
Gradually changing, or tending to change, a morbid state of the functions into one of health. Burton.

Al”ter*a*tive, n.
A medicine or treatment which gradually induces a change, and restores healthy functions without sensible evacuations.