With the objective of investigating more thoroughly the relationship between ascorbic acid and platelet aggregation (PA) in particular, in vitro and in vivo studies were made whether interferences exist, Scaling amounts of ascorbic acid were added to platelet-rich plasma (PRP) samples to determine the level at which the inhibition of the PA was induce by ADP and arachidonic acid (AA), and endoplatelet malondialdehyde (MDA) concentrations decreased. Changes in PA and MDA were not observed in the PRP control samples Also, in 10 healthy volunteers, an i.v. infusion of ascorbic acid (2 g) produced PA inhibition and a reduction of MDA concentrations.