Abstract: The object of this study was to conduct the ability of two medicinal herbs, namely rosemary and parsley, for amelioration of aflatoxicosis in Oreochromis niloticus. Two herbs’ extracts at three concentrations of either (0, 2 and 4 g kg-1 b. wt. divided into 2 doses at the start and the 6th day of the experiment) and three concentrations of aflatoxin B1, (AFB1 0, 9 and 18 mg kg-1 b. wt. as a single intraperitoneal administration) were tested either individually or in combination. The herbs and AFB1 were dissolved in Dimethylsulphoxide (DMSO 25%) and injected to fish groups. Sixteen groups of fish were investigated in this study, where A group (control) was injected with saline 0.89%, group B injected with DMSO (control solvent), groups F1 and F2 were injected with AFB1 alone (9 and 18 mg kg-1 b. wt., respectively), R1 and R2 groups were injected with rosemary alone (2 and 4 g kg-1 b. wt., respectively), groups F1R1, F1R2, F2R1 and F2R2 were injected with AFB1 + rosemary, while groups P1 and P2 were injected with parsley alone (2 and 4 g kg-1 b. wt., respectively); however, F1P1, F1P2, F2P1 and F2P2 groups were injected with AFB1 + parsley. At the 12th day of the experiment, blood and liver samples were taken from each group. The results indicated that the AFB1 injected groups revealed a significant increase in mortality rate (MR%) compared with AFB1-not injected, group F2 was the highest while F1R1 and F1P1 were the lowest in MR% among all AFB1 injected fish groups. Also, AFB1 led to reduction of haemoglobin (Hb), total protein (TP) and globulin (GL) concentrations and increase in activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). These alterations were significantly ameliorated when fish were injected with herbs’ extracts. AFB1 residues showed that the herbs level of 2 g kg-1 b. wt. have higher potency of reducing the AFB1 residues than the level of 4 g kg-1 b. wt. in case of AFB1 level 9 mg kg-1 b. wt. While, in case of AFB1 level 18 mg kg-1 b. wt., the groups F2 and F2P1 showed absence of AFB1 residues. Microscopically, AFB1 presented histopathological changes in hepatopancrease which increased in severity with increasing AFB1 level. These lesions may become less severer in all fish groups injected with AFB1 combined with herbs’ extracts especially with the lowest levels of herbs’ extracts and AFB1. So, this study concluded that either of rosemary or parsley was found to be safe and successful in protection from aflatoxicosis, particularly at the low level.