ABSTRACT: Importance:Dual anti-platelet therapy represents standard care for treating patients with ST-segment elevation myocardial infarction (STEMI). Ticagrelor is a direct-acting P2Y12 inhibitor and, unlike clopidogrel and prasugrel, does not require metabolic activation. Objective:To evaluate whether chewing a loading dose (LD) of ticagrelor, 180 mg, vs traditional oral administration of an equal dose enhances platelet inhibition at 30 minutes and 1 hour after LD administration in patients with STEMI. Design, Setting, and Participants:A randomized clinical trial was conducted in adults aged 30 to 87 years from May to October 2016 in a large tertiary care center. Analyses were intention-to-treat. Interventions:Fifty patients with STEMI were randomized to either chewing an LD of ticagrelor, 180 mg, or standard oral administration of an equal dose. Main Outcomes and Measures:P2Y12 reaction units were evaluated using VerifyNow (Accumentrics) at baseline, 30 minutes, 1 hour, and 4 hours after LD. Results:Baseline characteristics were similar in both groups. The mean (SD) of P2Y12 reaction units in the chewing group compared with the standard group at baseline, 30 minutes, 1 hour, and 4 hours after ticagrelor LD were 224 (33) vs 219 (44) (95% CI, -16.77 to 27.73; P?=?.26), 168 (78) vs 230 (69) (95% CI, -103.77 to -19.75; P?=?.003), 106 (90) vs 181 (89) (95% CI, -125.15 to -26.29; P?=?.005), and 43 (41) vs 51 (61) (95% CI, -36.34 to 21.14; P?=?.30), respectively. Platelet reactivity in the chewing group was significantly reduced by 24% at 30 minutes after LD (95% CI, 19.75 to 103.77; P?=?.001). The relative inhibition of platelet aggregation in the chewing vs the standard group were 51% vs 10% (95% CI, 13.69 to 67.67; P?=?.005) at 1 hour and 81% vs 76% (95% CI, -12.32 to 16.79; P?=?.24) at 4 hours, respectively. Major adverse cardiac and cardiovascular event rate at 30 days was low (4%) and occurred in 1 patient in each group (95% CI, 0.06 to 16.93; P?>?.99). Conclusions and Relevance:Chewing an LD of ticagrelor, 180 mg, in patients with STEMI is feasible and facilitates better early platelet inhibition compared with a standard oral LD. Larger studies are warranted to see if our preliminary findings translate into clinical outcomes. Trial Registration:clinicaltrials.gov Identifier: NCT02725099.