Toxicological evaluation of pure hydroxytyrosol

► Hydroxytyrosol is endowed with manifold healthful activities. ► The European Food Safety Authority authorized a health claim for hydroxytyrosol as antioxidant. ► Hydroxytyrosol is usually consumed as part of complex mixtures. ► Hydroxytyrosol is now available as pure compound. ► Following a toxicological evaluation of hydroxytyrosol we propose a NOAEL of 500mg/kg/d. Of all the phenolic constituents of olives and extra virgin olive oil, hydroxytyrosol is currently being actively exploited as a potential supplement or preservative to be employed in the nutraceutical, cosmeceutical, and food industry. In terms of safety profile, hydroxytyrosol has only been investigated as the predominant part of raw olive mill waste water extracts, due to the previous unavailability of appropriate quantities of the pure compound. We report the toxicological evaluation of hydroxytyrosol and, based on the results, propose a No Observed Adverse Effects Level (NOAEL) of 500mg/kg/d.