In the past few years, many studies have started to reveal a range of complex biological effects produced by high-frequency radiations, such as THz radiations. Despite their relatively low energy, THz radiation can cause changes in cell adhesion and migration, DNA damages, and stem cell differentiations. Some of these changes may be attributed to the temperature changes associated with the THz radiations, but most cannot be explained by these thermal effects. They are possibly the results of unknown biological perturbations caused by the radiation. Circumstantial evidence suggests that these effects are highly cell type-specific, but the lack of systematic studies hinders any further conclusions. We are conducting a detailed investigation on the impact of THz radiations, at various wavelengths, on DNA and RNA synthesis in a panel of mammalian cell lines. The outcome of this work is the establishment of a more comprehensive picture on the dosage-, wavelength-, and cell type-dependent effects of THz radiation. Furthermore, we are investigating the potential effect of THz radiation on two organismal models: C. elegans development and planarian regeneration. These invertebrate model systems provide a convenient in vivo platform for the analysis of the effects of THz radiation on cell renewal, migration, and differentiation.