A dose-related response is a human response to a stimulant — or to any active substance — that varies according to the amount exposed to: more dose, more effect. The principle underlies all of toxicology and pharmacology: caffeine sharpens alertness at one cup and produces jitters and palpitations at six; alcohol relaxes at one drink and impairs at four. The response curve is rarely a straight line — effects may plateau, reverse at high doses, or show thresholds below which nothing happens. Regulators use dose-response data to set acceptable daily intakes, maximum residue limits, and safe exposure levels, identifying the dose where effects begin and applying safety margins. Paracelsus stated the founding rule five centuries ago — the dose makes the poison — and every additive approval and nutrient upper limit since has been an exercise in mapping the response to the dose.