One of the general exceptions provided in the Penal Code 1860 goes on to exempt persons who happen to be incapable of judgment by reason of intoxication caused against his will. Section 85 categorically says that nothing is an offence which is done by an intoxicated person who, at the time when he was doing it, is, incapable of knowing the nature of the act; or he is incapable of knowing that what he is doing is either wrong, or contrary to law. A proviso to this section says that the thing which intoxicated him has to be administered to him without his knowledge or against his will.
Section 86 further speaks about particular intent or knowledge committed by one who is intoxicated. It says that when the thing that intoxicated the accused person was not administered to him without his knowledge or against his will, it will be presumed in cases where an act done is not an offence unless done with a particular knowledge or intent, that a person who does the act in a state of intoxication, had the same knowledge as he would have had if he had not been intoxicated.
As far as murder under section 302 is concerned under the Penal Code, a necessary element of murder is knowledge or intention. Therefore, in case of murder by an intoxicated person, the defence of intoxication can only be taken successfully when the intoxication happens owing to a thing administered on the accused murderer without his knowledge or against his will and not otherwise. In cases when the intoxicant is administered without his knowledge or against his will, the law will draw a presumption of his having the knowledge or intention that he could have, if he were not intoxicated.