Table 1.

Sample Reports of the Toxicity of Selected Phytochemicals.^a

	Lethal Dose 50% (LD50)	Toxic Dose Low (TDLO)
Resveratrol	No published data found	<2 g/d110 (human)
Lycopene	>3 g/kg (mouse)111	1.43 g/kg (human; http://www.centerchem.com/Products/DownloadFile.aspx? FileID=7345)
Curcumin	5 g/kg112 (rat); ≥2 g/kg113,114 (mouse)	12.6 g/kg (https://www.spectrumchemical.com/MSDS/TCI-C2302.pdf)
Saffron	>0.6 g/kg (rodents)115	No published data found

^a The phytochemicals with protective properties are all toxic at some high dose, which varies with how it is prepared, how delivered, and how assessed. Typically, the toxicity of something for whole animals is assessed as the LD₅₀ (the dose lethal to half the cohort tested); for humans as the TDLO (the lowest dose at which toxicity is detectable); and for cells in vitro as the IC₅₀ (half the concentration that fully “inhibits”/kills the cells). In animals, TDLO measures have been devised to test a range of responses, including skin irritation, corneal irritation, reproductive success, and DNA damage (genotoxicity). As a generality, the tissue-protective properties of the phytochemicals discussed below (and of many others) are apparent at doses that are not toxic by any of these measures.