Secondary metabolites of certain fungi produce toxins under favorable conditions especially while growing on different food grains. Mycotoxins are among major threats to growing poultry industry and human beings. Aflatoxins are closely related, biologically active fungal metabolites and commonly produced by Aspergillus species. A research was carried out to evaluate the ability of Aspergillus flavus for Aflatoxin B1 production using rice, wheat and maize as substrates. Lethal effects on growth performance parameters, hematological and histopathological of graded doses of aflatoxin B1 in quails under experimental conditions were observed. Effect of Aflatoxin B1 on humoral immune response to Newcastle Disease virus vaccine in quails were determined. Biological detoxification of Aflatoxin B1 by Saccharomyces servisiae was evaluated in quails. Comparative evaluations of different commercially available toxin binders were checked. All these experiments were carried out till the six weeks (42 days). Aspergillus flavus was identified on the basis of macroscopic and microscopic characteristics. Rice, wheat and maize grains was used as substrate to check the level of Aflatoxin B1 produced by inoculating an aqueous suspension of 106 spores/ml. Aflatoxin B1 checked by Thin Layer Chromatography (TLC) and quantified by High Performance Liquid Chromatography (HPLC). Quails were reared under standard management conditions in five groups (A, B, C, D and E) having sixty each. Each group was further divided in two independent units. Diets offered to groups were control (without toxins), 0.25, 0.50, 1 and 2 mg Aflatoxin B1/kg feed. One unit of each group was vaccinated with Newcastle Disease Virus (NDV) vaccine while other was not and studied the lethal effects on growth performance, blood parameters, immune response and histopathology of vital organs. At the end of the experiment, it was found that the deleterious effects of Aflatoxin B1 were dose and duration dependent. As the level of the toxin was increased, the lethal effects were prominent. The growth performance parameters including gain in body weight, feed intake and feed conversion ratio was adversely affected at high doses. The body weight gain was significantly reduced in Aflatoxin B1 treated groups as compared to control group. Similarly feed intake and feed conversion ratio were significantly different from the control group. The hematological studies exhibited that aflatoxin B1 significantly reduced the hemoglobin, packed cell volume and total leukocyte count whereas the erythrocyte sedimentation rate was significantly increased as compared to control group. The immune response against NDV vaccine was adversely effected in Aflatoxin B1 treated groups and values of Antibody titer in AFB1 were significantly low as compared to group A( control) In the second experiment, Saccharomyces cervisae (SC) dried powder was mixed in basal quail diet having 0.5mg Aflatoxin B1 for all experimental groups and control was without toxins. SC was added at levels of 0.5 gm, 1.0 gm and 2.0 gm /kg of feed. It was recorded that Saccharomyces cervisae (yeast) have the potential to remove the deleterious effects of Aflatoxin B1. Yeast effectively detoxified the Aflatoxin B1. The results recorded of growth performance and other parameters were non-significantly different from the control group. Chemical detoxification of Aflatoxin B1 was evaluated in quails using commercially available toxin binders. Toxin binders used were activated charcoal, kaoline, Myco AD and selenium plus vitamin E and mixed in basal quail diet having 0.5mg Aflatoxin B1 for all experimental groups and control was without toxins. The Myco AD and selenium plus vitamin E showed the highest detoxification potential as compared to other chemical toxin binders. Groups E and F showed the results of growth performance, hematological, immune response and histopathological were non-significantly different from the control group (A). Kaolin was moderately detoxifying the toxin. Presence of aflatoxin B1 in soft tissues was checked by TLC and quantified using HPLC. The liver exhibited the residues of Aflatoxin B1 at high doses of toxin. Group D and E rearing on feeds having 1mg AFB1 /Kg feed and 2mg AFB1 /Kg feed of toxin showed the residues of AFB1 in liver and kidney. Statistical means for growth performance parameters, hematological, immune response and histopathological scores in each subunit of quails were analyzed by applying one way ANOVA and Duncans‟s Multiple Range (DMR) test at 95% probability. Aflatoxin B1 is lethal and lowers the performance of birds. The lethal effects can be detoxified by biological and chemical means to lower the economic losses to poultry industry. It can be concluded that biological detoxification is preferably better as compared to chemical detoxification.