This study was conducted to follow up broiler chickens during aflatoxicosis by feeding them with ration contaminated with Aflatoxin B1 (AFB 1) for a period of six weeks from 0 to 42 days; and to evaluate the effectiveness of Nutritox (a commercial biological antimycotoxin) in alleviating aflatoxicosis. One hundred broiler chicks of one day old were divided into four groups; each of twenty five chicks; the 1^st group received a standard ration and kept as a control group, the 2^nd group received a ration contaminated with 1 mg AFB1/kg ration, the 3^rd group received ration contaminated with1 mg AFB1/Kg ration plus Nutritox with a dose level 0.5gm/kg ration, the 4^th group received a standard ration plus Nutritox with a dose level of 0.5 gm/kg ration. Chicks in all groups were weighed at the first and the end day of the experiment (42 days) and feed consumption for each group was calculated, blood and tissue samples were collected from each group at the end of the experiment. Results of the experiment revealed that AFB1 induced reduction in the body weight and feed consumption, while addition of Nutritox to the ration of chicks received AFB1 contaminated ration resulted in an improvement in the body weight and feed consumption compared with that group received contaminated ration with AFB1 which elicited a significant increase in the activity of liver and kidney enzymes with decrease in calcium and inorganic phosphorus levels. Addition of Nutritox to contaminated ration induced a significant improvement in enzymes, calcium and phosphorus levels. Regarding the histopathological results, examination of the internal organs sections revealed typical lesions of Aflatoxicosis, but addition of Nutritox to AFB1 contaminated ration decreased the severity of the pathological lesions. The body weight of chicks of the control group, feed consumption and most of the studied biochemical parameters were improved, these findings suggest that the AFB1, caused many alteration in the growth performance, and the biochemical parameters which are confirmed by many pathological changes in the internal oranges of the chicks. Addition of Nutritox to AFB1, contaminated ration was effective in alleviating the toxic effects associated with Aflatoxicosis.