Human platelets were collected from healthy human donors and platelet concentrates (PC) were prepared according to standard blood banking procedures. PC were treated with vehicle (Veh), 10 μM resveratrol (Resv.), 10 μM trans-trimethoxy-resveratrol (TMR) or 5 μM aspirin (ASA) prior to storage and stored for up to 5 days at room temperature with agitation. Platelet poor plasma was generated from each sample and used as a reference denoting 100% light transmittance. Aggregation was initiated by addition of 10 μM ADP (A–B), 10 μg/ml collagen (C–D) or 5μM ADP + 5 μg/ml collagen (E–F). Representative traces from one donor at day 5 are shown (A, C, E). Dual agonist stimulation was only performed at day 5 post-storage (F). Mean +/− SEM. n = 4 Statistical significance was determined by one-way (F) or two-way (B, D) RM ANOVA with Dunnett’s post-test. **p<0.01