Introduction. According to the bibliographic data, in the aerial parts of the B. incana L. species, there are various chemical compounds: apigenin, luteolin dihidroquercetin, gallic acid, neochlorogenic acid, due to which the plant material possesses antibacterial, spasmolytic and hypotensive properties. The plant is toxic due to its alkaloid content. Aim of the study. Spectrophotometric determination of total phenolic and flavonoid content in plant materials B. incanae herba and B. incanae radices. Materials and methods. Plant materials were collected from spontaneous flora in different periods (june, september, november). Dosage of total flavonoid and polyphenol was performed by the spectrophotometric method, using 70% ethyl alcohol as solvent. Optical density was measured at Metertech UV / VIS SP 8001 spectrophotometer at wavelengths 400 and 760 nm. Results. The total phenolic contents (TPC) of hydroetanolic extracts of sp. B. incana L. were determined according to the Folin–Ciocalteu procedure and it were expressed as gallic acid equivalents; flavonoid contents were expressed as luteolin equivalents. Extracts from the aerial parts had higher total phenol and flavonoid contents than roots extracts. The highest level of total flavonoid content was determined in the aerial parts collected in june (0,30%), followed by the plant material collected in september (0,273%) and then in november (0,16%). The major content of flavonoids in roots was found in plant material collected in september (0,11%), followed by november (0,03%) and then in june (0,01%). The TPC was found to be the highest in aerial parts collected in june (8,02%), followed by september (6,80%) and november (5,74%). In the case of roots of sp. B. incana L., the highest level of TPC was found in samples collected in september (4,80%), followed in june (2,77%) and then in november (2,54%). Conclusions. The significant diferences in total phenolic content were found between aerial parts and roots of sp. B. incana L. The lowest flavoids and phenol level were determined in roots. It was proved that the collection period of plant materials influence the quantitative content of the phenolic compounds.