Graphene quantum dots (GQDs) have been of excessive curiosity resulting from their measurement and optical traits, which improves when purposeful teams are added to their borders and defects. On this work, the in vitro toxicity of aqueous dispersion of GQDs (w/wo amino-functionalization) was investigated in two totally different mobile fashions (S. cerevisiae and H9c2 cell line). Leads to yeast counsel that when at as much as 25 % quantity focus, the impact of all examined GQDs was solely inhibitory, and, in each mobile fashions, the poisonous impact is rigorously dose-dependent. The comparability of IC50 values of all of the examined GQDs reveals no important variations amongst them, pointing to non-carbonized citric acid because the extra poisonous precursor. The obtained information counsel that functionalization makes GQDs much less poisonous, being the one functionalized with thioacetamide barely extra poisonous, adopted by those functionalized with thiourea and glutathione, respectively. Outcomes verify that their toxicity is traits as an entire, and never because the sum of the toxicity of the precursors. In each fashions, concentrations as much as 2 % confirmed no important toxicity. Lastly, fluorescence microscopy photographs counsel that GQDs work together with the mobile membrane and enter within the cell, manifesting fluorescent properties.