Gel

Gels are an unknown substance that acts as a recovery item in several games in the series. They come in many varieties of varying effects and strengths, and are presumably consumables.

Mysterious Substance
The games are never clear on exactly what gels are, what they are made of, what they look like, how they are stored, or how they are consumed. That said, we can make inferences about gels based on their properties and references made by characters in-game. At least in Tales of Symphonia, we can infer that gels do not require advanced technology to make, as they are mass-manufactured in the underdeveloped world of Sylvarant. This also suggests that gels use natural fruit for flavor and ingredients. A quote from Lloyd Irving early in the game implies that gels provide enough sustenance to get by, meaning they are a simple food rather than a candy. However, their price makes their use as food uneconomical. As revealed through one of his special titles, Genis Sage hates gels, presumably for their taste or due to his affinity for cooking.

Types and Effects
There are six different kinds of gels, each with a different effect, and presumably a different flavor.

Apple Gel: Restores 30% of a character's HP.

Orange Gel: Restores 30% of a character's TP.

Melange Gel: Restores 30% of a character's HP and TP.

Lemon Gel: Restores 60% of a character's HP.

Pineapple Gel: Restores 60% of a character's TP.

Miracle Gel: Restores 60% of a character's HP and TP. Highly sought-after.