The present study inspects the effect of phenol as one of environmental xenobiotic compound on the histology and histocemistry of liver, gills and spleen of Oreochromis aureus (O.aureus) juveniles. Fish were subjected to three
sub-lethal concentrations of phenol (20%, 40% and 80% of LC50) for seven days.
The liver, gills and spleen were studied from the histopathological and histochemical point of sight. Histopathological changes viz degeneration, necrosis, severe hemorrhage pynknosis and distinct cellular proliferation in the
prescribed organs of fishes exposed to phenol were observed. Further,detachment of gill epithelium (GE), marked proliferation of gill epithelium (Hyperplasia, H) with distinct shortening of lamellae were recorded. Even
though, complete fusion of gill lamellae, enhanced connective tissue disposition and blood permeation were also induced due to phenol exposure. Furthermore, histochemical annotations affirmed reduction of carbohydrate store due to
oxidative stress caused by phenol publicity. Marked rise of gills mucoplysaccharides which impedes fish respiration were reported. DNA was also amplified in tested organs after phenol exposure, signifying carcinogenesis of phenol.