Cadmium (Cd) is one of the most harmful heavy metals and influences important metabolic processes causing serious damages in many organs. It is well known that Cd could provoke generation of reactive oxygen species (ROS) and DNA damage. Some antioxidants (such as vitamin C, vitamin E and N-acetyl-L-cysteine) have been used as protectors against cadmium-induced toxicity. On the other hand, lichens have long been investigated for biological activities; mainly antimicrobial and antioxidant activities. In this study, we aimed to determine whether D. intestiniforme aqueous extracts (25 and 50 ppm) conferred a protection against cadmium chloride (CdCl2) (30 ppm) induced genetic and oxidative damage in human whole blood cultures. Biochemical parameters (total antioxidant capacity [TAC] and total oxidative status [TOS]) were examined to determine oxidative effects. The micronucleus (MN) test was used for analysing genotoxic influences. In addition nucleer division indeks (NDI) was used to determine cytotoxicty. Oxidative damage by CdCl2 in erythrocytes decreased with application of lichen extracts. Similarly, the positive effect of lichen aqueous extracts in decreasing the incidence of MN in comparison with an unprotected level was attained when cultures were treated simultaneously with CdCl2 and the extracts (P<0.05). The findings of this study firstly revealed that D. intestiniforme modulated Cd-induced genetic and oxidative damage in human blood cultures due to its antioxidant and/or detoxifying nature.