Remedial describes something provided to cure, or something designed to get a student up to speed who is behind. (adjective)
A potion that is supposed to make you feel better when you drink it is an example of something that would be described as aremedial potion.
A class that is supposed to catch students up on basic math concepts that they should know, is an example of somethingthat would be described asremedial math.
See remedial in Webster's New World College Dictionary
adjective
providing, or intended to provide, a remedy
☆ Educ. designating or of any special course of study for helping students overcome deficiencies in specific skills, abilities, or knowledge: remedial reading