Going by the D&D player's handbook, and how it seems to be implemented in BG3, the spell is supposed to cure any disease or one of a select few conditions - blinded, deafened, paralyzed, or poisoned. But in the game, the tooltip for lesser restoration just says that it "removes one disease or condition afflicting a creature", which implies that it should work for any condition. I spent most of my game thinking the spell was bugged because it wasn't removing effects like 'entangled' and 'charmed'.
