In toxicology, the<unk>  (Toxic Dose Low, TDLo) is the lowest dosage per unit of bodyweight (typically stated in milligrams per kilogram) of a substance known to have produced signs of toxicity in a particular animal species. When quoting a TDLo, the particular species and method of administration (e.g. ingested, inhaled, intravenous) are typically stated.
Lowest published toxic dose
Maximum acceptable toxicant concentration
Relative biological effectiveness
Reference dose
Effective dose 
Virtually safe dose
Lowest-observed-adverse-effect level
Equivalent dose