TDLo

In toxicology, the Lowest published toxic dose (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 an TDLo, the particular species and method of administration (e.g. ingested, inhaled, intravenous) are typically stated.
See more at Wikipedia.org...