This article explores the use of brain stimulation as a tool of neuroplasticity. Recent studies have shown that brain stimulation with weak direct currents is a technique used to generate prolonged modifications of cortical excitability and activity. Transcranial direct current stimulation (tDCS) generates modulations of excitability. The efficacy of electric brain stimulation is defined by the combination of strength of current, size of stimulated area, and stimulation duration. The two main fields of clinical application on tDCS are: the exploration of pathological alterations of neuroplasticity in neurological and psychiatric diseases, and the evaluation of a possible clinical benefit of tDCS in these diseases. Further studies are needed to explore this area if prolonged, repetitive, or stronger stimulation protocols, for which safety has to be assured, could evolve into clinically more relevant improvement. This article reinforces the fact that brain stimulation with weak direct currents could evolve as a promising tool in neuroplasticity research.