The effect of aqueous extract from Inonotus obliquus on the mitotic index and some enzyme activities in human cervical uteri tumour cells HeLa S3 in vitro was evaluated. It was concluded that Inonotus extract inhibited the growth of tumour cells. The fungal extract caused a decrease of the cell protein amount and mitotic index value. Moreover, this extract disturbed metabolism in cells caused decreased activity of LDH, HBDH, MDH, GGT and increasing the activity of catalase.