Terahertz technologies have recently been applied to develop high resolution imaging. Since practical portable systems can be designed, the possibilty has emerged to easily screen for biohazards and concealed objects, a procedure which usually requires remote analysis. Applications of THz are also envisaged in the medical field, because this technology offers a degree of accuracy never reached before in molecule analysis. Skin abnormalities and dental health care are two promising targets of THz applications. Nevertheless, potential hazards and health effects of THz exposure should be monitored carefully, particularly since some data suggest induction of genomic instability.