© 2018 Platelet aggregometry assays are generally used for the analysis of platelet function but can also be adapted for further research and therapy focused applications. This method describes the procedures for the preparation of human platelet-rich plasma (PRP) and platelet-poor plasma (PPP) for the assessment of human platelet aggregation induced by agonists such as platelet-activating factor (PAF), thrombin, collagen, adenosine diphosphate (ADP), arachidonic acid, etc. ¿ This method can be applied in vitro to evaluate the aggregatory effects of these agonists and to assess the antiaggregatory effects of several bioactive antiplatelet agents (compounds of natural or pharmacological origin) in human PRP.¿ This versatile method can be used in both basic and clinical research for the assessment of platelet aggregation (a major cardiovascular risk factor), platelet agonists, and inhibitors, in physiological or pathological conditions.¿ This method can be adapted to assess platelet activity in postprandial and intervention studies ex vivo.