The Basic Principle
The basic underlying purpose and direction of all the directives of the Islamic Shari`ah  is the purification and cleansing of the human mind, body and soul. It is with this basic stress in its general directives that the Shari`ah also requires man to keep in perspective the criterion of the ‘good’ and the ‘bad’; the ‘fit’ and the ‘unfit’; the ‘clean’ and the ‘unclean’ in his selection of what may and may not to be eaten.
The Qur’an (Al-Maaidah 5: 4) says:
All things suitable [for eating] have been permitted to you.
Thus, the stipulation of the criterion of the ‘suitable’ and the ‘unsuitable’ is the basic guidance of the Shari`ah regarding the lawful and the prohibited in edibles . The Shari`ah has generally considered this basic guidance to be sufficient for man. In fact, this is the reason why the Shari`ah has not felt the need to give an exhaustive list of what is suitable for eating and what is not, as man’s natural inclinations and instincts generally have correctly guided him in making the decision. History bears witness to the fact that man has generally not felt attracted toward serving the flesh of wild and carnivorous animals, birds of prey and certain insects  on his table. He has generally considered his horses, mules and dogs to be of domestic utility for him, rather than to serve his hunger. He has also remained absolutely clear about the ‘unsuitability’ of his own defecations and those of other living things. The same has also generally been the case of all such things that intoxicate him and affect his consciousness and his faculty of reasoning and understanding. As stated earlier, it is for this reason that the Shari`ah, after giving this basic guidance regarding the lawful and the prohibited in edibles, has not felt the need to give an exhaustive list of what man should and should not eat. The prohibition of canines, birds of prey , such animals that due to their habit of eating filth develop a kind of stench in them  and mules  etc. that has been reported in some narratives ascribed to the Prophet (pbuh) are, in fact, an explanation of this natural inclination and instinct of man. The prohibition of liquor and intoxicants also falls in the same category. At the time of the revelation of the Qur’an, when people repeatedly inquired about liquor, pointing out to some of its advantages, the Qur’an adamantly declared that the sin involved in drinking liquor far exceeds any of its advantages . Then, later on, in Surah Al-Maaidah, the Qur’an emphatically declared that drinking liquor, due to its potentially negative consequences is an ungodly and a satanic deed, which, under all circumstances, therefore, must be avoided.
The Qur’an (Al-Maaidah 5: 90) says:
O you, who believe, liquor, gambling, animals slaughtered at shrines and food distributed by gambling through arrows are all unclean, satanic deeds, therefore refrain from them, so that you may be successful [in the test of this life].
All these directives of the Qur’an and those mentioned in narratives ascribed to the Prophet (pbuh) are, basically, a reference to and a reminder of these natural instincts and inclinations of man. There, indeed, have been scattered instances where a particular society has ignored these natural instincts and inclinations and has deviated from them. Nevertheless, on the whole man has, generally, quite strictly conformed to these instincts and inclinations, in choosing between what should and should not be eaten. It is for this reason that the Shari`ah has not gone into the, already conformed with, details of what a man may and may not eat, and has, therefore, restricted its guidance to the few instances in which man could have confused right from wrong, had he taken a decision in the light, merely, of his natural instincts and inclinations. For example, being an omnivorous animal, should pig be grouped with the eatable grazing animals or the uneatable carnivorous animals? All animals are killed before being eaten. What if an animal dies a natural death? Should it now be grouped with the ‘edibles’ or the ‘inedibles’? Should blood – being a part of an animal’s body – be grouped with the edible parts of its body – like meat, fat, bones etc. – or inedible parts – like the residual defecation in its stomach? Does it make any difference that the animal is slaughtered without pronouncing God’s name upon it or even if it is slaughtered for any other deity besides God? Man, it is obvious, could not have answered these questions, with any degree of certainty, without God’s guidance, in this regard. Thus, for the guidance of man, God has given clear answers regarding these four items (i.e. flesh of swine, flesh of dead animals, flowing blood and animals slaughtered for other deities) and has grouped each of them with the inedible group of things. In fact, a close look at the directives of the Shari`ah shows that it has restricted its directives to these four items, about which man was not in a position to take a decision on his own, regarding whether these items should be grouped with the eatable things or the uneatable things.
The Qur’an, in Al-An`aam 6: 145, says:
Say [O prophet]: ‘In what has been revealed to me, I find nothing prohibited from the things that a person eats, except carrion, flowing blood, the flesh of swine – because these are all unclean things – or any flesh that has been sacrilegiously consecrated for anything other than God’. Nevertheless, whoever is driven by necessity, intending neither to sin nor to transgress, will find your Lord very Forgiving, Eternal in mercy.
At another instance (Al-Baqarah 2: 173), the Qur’an says:
Only carrion, blood, flesh of swine and that which is consecrated for anything other than God is prohibited for you. Even, in these things, whoever is driven by necessity, intending neither sin nor transgression, there shall be no sin upon him. Indeed God is extremely Forgiving, Eternal in mercy.
Exactly the same directive has once again been repeated in Al-Nahl 16: 115, with hardly any alteration in words. Notice the limiting style in all these instances. In the first case, the words “In what has been revealed to me, I find nothing prohibited from the things that a person eats, except…” , while in the second verse, the opening word “only…”  has clearly restricted the prohibitions prescribed by God, in the case of edibles, to the mentioned four items only.
The above explanation completely sums up the basic directives of the Shari`ah with regard to edibles. To avoid any confusion, there are, however, some explanations, clarifications and extensions of these basic directives, also given in the Qur’an. These clarifications and extensions are explained in the following paragraphs:
Extensions/Limitations of the Prohibition of Carrion
a) Animals that Die in an Accident or due to an Injury
As is clear from the above explanation, carrion – flesh of dead animals – was clearly prohibited by the Qur’an. Nevertheless, there could still have remained some doubt regarding whether this prohibition applies only to animals that die a natural death or would it also extend to animals that die because of an accident or an injury caused by other animals or by a fall etc. The Qur’an, in Al-Maaidah 5: 3 completely clarified the situation and removed all doubts that could have existed in this regard. It declared: