A non-alcohol mouthwash composition without chemical antibacterial medicament is disclosed. The non-alcohol mouthwash composition includes from 0.03% to 1.5% of γ-polyglutamic acid (γ-PGA) and from 0.5% to 4% of surfactant, all percentages based on the total weight of the mouthwash composition. The non-alcohol mouthwash composition preferably includes from 0.4% to 1.5% by weight, or more preferably from 0.8% to 1.3% by weight, of γ-PGA. Containing no chemical antibacterial medicament, the non-alcohol mouthwash composition can effectively inhibit bacterial growth in the oral cavity without irritating the oral mucosa.