In toxicology, the lowest published toxic dose (Toxic Dose Low, TD) 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 TD, the particular species and method of administration (e.g. ingested, inhaled, intravenous) are typically stated.
The TD is different from the LD (lethal dose) which is the dose causing death in 50% of people who are exposed or who consume the substance.