Depressed patients typically show increased attention toward negative emotional material (negativity bias) and reduced attention toward positive emotional material (positive attenuation). According to imaging studies, this processing bias may be associated with dysfunction in a distributed neural network, including the ventro-medial prefrontal cortex (vmPFC). In fact, structural differences and reduced vmPFC responses toward reward- or safety-signaling stimuli play important roles in various affective disorders such as social phobia or gambling disorder. Thus, facilitating the excitability of the vmPFC by non-invasive brain stimulation to reduce negativity biases/positive attenuation and improve reward and safety processing seems to be a reasonable approach towards novel therapeutic interventions. One widely used and effective method for non-invasively modulating brain activity is transcranial direct current stimulation (tDCS), and this method is also particularly suitable for stimulating the vmPFC. In a series of magnetencephalography (MEG) studies, we were able to show that excitatory compared to inhibitory vmPFC-tDCS stimulation resulted in a relative positivity bias of emotional scene and emotional face processing as well as stronger expectancy and processing of rewards. We also found that vmPFC-tDCS reduces framing effects and irrational risk behavior in monetary gambling tasks, likely due to modulated loss and risk aversion. These findings indicate that vmPFC-tDCS should be tested clinically as a potential add-on therapy for mood and addiction disorders.