Despite the great importance of pharmaceutical products in our daily life, they have negative effects on the environment; where it may threatens many non-target organisms. The present study provides an integrated framework of contribution to understanding the toxicity of three commonly used pharmaceutical products (amoxicillin, naproxen and tramadol) on the micro-green alga Pseudokirchneriella subcapitata. The impact of pharmaceutical pollution on aquatic organisms can be evaluated by assessing its physiological response. The alga was exposed to sub-lethal concentrations (LC10, LC25 and LC50) of each tested pharmaceutical to determine its impact on growth behavior, pigments, total lipids, protein and carbohydrate content. The obtained results clarified that, exposure to the pharmaceuticals by their sub-lethal concentrations mostly resulted in a decrease in cell density up to 66.25% by amoxicillin and 37.24% by tramadol within LC50, although exposure to low naproxen concentration promoted cell density (up to 21.7%) after 24h. Amoxicillin (67.74 - 97.44%) followed by tramadol (59.67- 93.55%) significantly reduced the content of the pigment after 96h but in a different manner, however except within LC50, naproxen induced both carotenoids (4.55- 11.61%) and chlorophyll-a (1.54 - 9.23%) during the first 24h. The tested pharmaceuticals also reducing protein, carbohydrates and total lipid content of P.subcapitata at the end of the experiment by ratios up to 96.7, 86.2 and 74.9% respectively. Due to the dramatic effects of pharmaceuticals on the aquatic non-target organisms all new pharmaceutical products must undergo an environmental risk assessment test during and after the development of the product to obtain marketing approval.