From the Super Mario Wiki
Earlier Times is an item from Super Mario RPG: Legend of the Seven Stars. The player must give the Frog Student fifteen Frog Coins to obtain this item. Earlier Times can only be used in battle, and the effect is that it starts the battle over from the start. When this occurs, all battlers' parameters return to what they were at the beginning of the battle. In addition, any items used, except for Earlier Times, will be returned to the player.