OBJECTIVE: In vitro cell and blood compatibility of three dietary supplements, comprised of multiple plant extracts, Pneumo Go (PG), Green active (GA) and Equistasi (Eq), and their main component, the phytocomplex Matrix U.B.® (Union Bio S.r.l.) (M), were evaluated. Moreover, preliminary in vivo tests were performed on GA in order to assess its ability to reduce pain in an animal model. METHODS: Cell compatibility was determined using fibroblasts (NIH3T3) and primary adult human microvascular endothelial cells (HMVECad) and the neutral red uptake test. Blood compatibility was evaluated by analyzing blood parameters after incubation of the products with sodium citrate anticoagulated whole blood. Thrombin time was determined by adding thrombin to aliquots of human plasma containing the samples. Clotting time was revealed by an automatic coagulometer. The in vivo analgesic effect of GA was evaluated in Wistar rats using the formalin test. RESULTS: M and PG reduced the percentage of viable NIH3T3 cells, indicating their interference in the cell cycle. GA and Eq stimulated fibroblast proliferation and neutralized the toxic effect of M. M and PG reduced HMVECad cell viability. GA and Eq did not affect cell viability as well as negative control. The hemocompatibility tests indicated that all the samples did not interfere with fibrinogen. The in vivo test carried out in male rats showed a significant analgesic effect of GA in all formalin-induced pain behaviors. CONCLUSION No hemotoxicity and good cell compatibility were found for all the tested samples. GA and Eq were the best candidates for further biocompatibility testing. Moreover, GA reduced pain in the animal model.