The immunosuppressive properties of rifampicin have been discussed in the literature for more than 30 years. It is hypothesized that rifampicin acts as a mild immunosuppressive agent in psoriasis rather than an antibacterial one. We report our studies on the therapeutic efficacy of rifampicin in guttate psoriasis. We try to give light on the mechanism of action of rifampicin in psoriasis. Our therapeutic results together with data from the literature revealed rifampicin to be a mild immunosuppressive agent. Its best effectiveness is in the guttate type of the disease.