Topic overview

Start with the big picture

A dose–response curve helps describe how toxic effects change as dose increases, using concepts such as threshold, slope, maximal effect, and LD50. Measures including NOAEL, LOAEL, Reference Dose, therapeutic index, and margin of safety support comparisons of hazard and safety. The route of exposure and toxicokinetic processes—including absorption, distribution, metabolism, and excretion—can shape systemic burden. Other factors include interactions between chemicals, acute versus chronic exposure, susceptibility across populations, and specific toxicological endpoints. The topic also introduces biomagnification, idiosyncratic reactions, risk assessment, and biomarkers such as blood lead or cholinesterase activity. Together, these principles provide a foundation for interpreting toxicological risk and response.