Peanut is an annually grown plant and the chiefly cultivated species is Arachis hypogaea L. Mainly three types of proteins, arachin, conarachin I and conarachin II are present in peanut. It is an important and cheap source of protein. It can also cause allergic reactions in human beings. The peanut protein contains two components, Ara h 1 and Ara h 2 which are mainly responsible to cause allergy. Different remedial measures have been proposed to fight with the allergenic property of peanut proteins such as treatment with peroxidase, phytic acid, active charcoal, and various enzymes to minimize allergenic effect. Improper storage of peanuts causes growth of a fungal organism that releases aflatoxin, which is a carcinogen to mammals. Use of aluminosilicate clay, gamma irradiation, ozonation methods have been discussed for aflatoxin decontaminated from peanut. In this critical review, we have given an overview of the different extraction procedures of the peanut proteins and pointed out the methodologies to minimize allergenic actions and detoxification of the aflatoxin contamination in peanut. © 2012 The Korean Society of Industrial and Engineering Chemistry.