The effect of caffeine mouth rinsing (CAF-MR) on cognitive performance has not been thoroughly investigated. To evaluate the effects of different concentrations of CAF-MR on selective attention in relation to perceived taste intensity. A total of 30 healthy and recreationally active male subjects were included in this randomized, double-blind, placebo-controlled crossover trial. Interventions included MR for 20s at rest with three different caffeine solutions (0.24% [60 mg/25 mL], 0.6% [150 mg/25 mL], and 1.2% [300mg/25 mL]), MR with 25 mL water (placebo), and no MR (control). Data on Victoria Stroop Test (VST) and the perceived taste intensity were recorded at five sessions. CAF-MR-300mg intervention significantly decreased completion time (from 62.93 ± 19.07 to 57.01 ± 16.74s, p = 0.002 in Part D), while CAF-MR-150mg intervention significantly decreased number of errors in Part D (7.00 ± 6.21 vs. 5.63 ± 5.76, p = 0.04) and Part C (8.77 ± 8.80 vs. 7.10 ± 7.11, p = 0.02). Perceived difficulty was significantly decreased both after CAF-MR with 150mg (5.57 ± 1.65 vs. 4.77 ± 1.98, p = 0.006) and 300mg (5.95 ± 1.77vs. 4.67 ± 1.96, p < 0.001). Perceived taste intensity for 300mg of caffeine was negatively correlated with completion time (r: ranged, 0.37 to 0.46, p ranged, 0.045 to 0.009) after 300mg, 150mg (p ranged, 0.04 to 0.005) and placebo (p ranged 0.044 to 0.03) interventions. This study is the first to demonstrate that CAF-MR shows dose-dependent effects on selective attention in healthy recreational males, such as improved speed (for 300mg caffeine), reduced error rate (for 150mg caffeine) and decrease in perceived difficulty (for 150 and 300mg caffeine).