tAnacardium occidentale L. (cashew tree) has been traditionally used to treat type 2 diabetes. Hereby wepresent results of free radical scavenging activity assay and in vivo toxicity and genotoxicity tests on redand white cashew stem bark Portuguese traditional herbal preparations (CSBTHPs) used to control type2 diabetes, standardized on the basis of the total phenolic content.A 2-week repeated dose toxicity study was performed with three doses (40.2, 127, 402 mg/kg/day) ofeach CSBTHP, administered by gavage to CD-1 mice (n = 28). Micronucleus test and comet assay wereperformed in CD-1 mice (n = 18) which received a single dose of 2000 mg/kg (p.o.) of each CSBTHP orcyclophosphamide 50 mg/kg (i.p.) or water (p.o.).The total phenolic content was 58.0 ± 0.4 mg gallic acid equivalents (GAE)/g cashew stem bark (CSB)in white CSBTHP and 51.3 ± 1.6 mg GAE/g CSB in red CSBTHP. Both red and white CSBTHPs exhib-ited concentration-dependent radical scavenging activity with IC50values of 180.7 ± 6.7 g/mL and143.8 ± 2.8 g/mL, respectively. No treatment-related effects on relative organ weights, biochemicalparameters and food intake were observed in the repeated dose toxicity study with both CSBTHPs. Inthe mice micronucleus test both CSBTHPs showed absence of bone marrow suppression and a similarfrequency of micronuclei in immature erythrocytes between treated and negative control groups. Thecomet assay revealed both CSBTHPs to be non-genotoxic.Concluding, both red and white CSBTHPs, standardized on the basis of the total phenolic content,revealed to be sources of natural antioxidants and devoid of a genotoxic risk. The daily oral administrationof doses up to 402 mg/kg of those CSBTHPs did not induce relevant signs of toxicity in mice