Intractable chronic itch is resistant to antihistamines, and difficult to treat, which significantly reduces quality of life. Here, we focused on GABA transporter 1 (GAT1) whose blockade might have an antipruritic effect by increasing endogenous GABA.The allergic contact dermatitis model of chronic itch was generated by applying 1-fluoro-2,4-dinitrobenzene (DNFB) onto the shaved neck skin using ICR male mice. Five days after sensitization by topical application of 50 µL 0.5% DNFB solution, mice were challenged repeatedly with 30 µL 0.25% DNFB solution on day 1, 3, 5, and 7. Scratching frequency was measured for 60 min on day 2, 4, 6, and 8, and the GAT1 blocker tiagabine (3 mg/kg, i.p.) was administered daily (twice a day) as protective treatment, or once at a single dose (1, 3 mg/kg, i.p.) on day 8 as therapeutic treatment. Neck skin and cervical spinal cord were collected on day 8 from mice after daily protective treatment of tiagabine for histological and immunohistochemical analysis, respectively.We found that both the protective and therapeutic treatments of tiagabine inhibited scratching behavior. While tiagabine did not change skin thickness, it tended to reduce epidermal thickness and mast cell numbers. Immunohistochemical analysis revealed that the number of FosB-positive GRPR-expressing neurons increased in the DNFB model was significantly decreased by tiagabine. Moreover, both GAT1 and GRPR were expressed in the superficial dorsal horn stained with IB4. Thus, endogenous GABA, which is increased by GAT1 inhibition, appears to act directly on GRPR neurons and control itch transmission.