Halal means lawful, and halal food are food items and drinks prepared under strict Muslim dietary laws.
Haram (unlawful) items include birds and beasts of prey like hawks and tigers, food that has been offered to idols, the flesh of animals that are already dead before slaughtering, blood and certain animals like monkeys and rats. The common non-Muslim food which are prohibited to Muslims include pork, lard and by-products of pork like ham, bacon and liquor.
Halal (lawful) animals, like chicken, sheep, cattle, must be slaughtered by Muslims because a short prayer is said when they are being slaughtered. Also, these animals are slaughtered with very sharp knives and in such a way as to effect (1) quick death and (2) thorough drainage of blood. Aquatic animals like fish need not be slaughtered because (1) they die quickly when they leave water and (2) they do not have much blood as birds and land animals.
Food items with animal gelatin and cakes and fruit punch with liquor added are also not permissible.
Islam teaches people to eat to live and not live to eat. As such, what one eats becomes important. Eating moderately and wisely is related to other undertakings of the life of a Muslim, like performing the daily prayers and fasting in Ramadhan. All these are instructions from God. So, if a Muslim eats haram (unlawful) items purposely, it is just the same as to say that he has no confidence in or respect for God’s Advice, he is even defiant. Thus, Muslims obey God’s Advice and consume only halal food to remain pure in body and soul as far as possible.
Non-Muslims who invite their Muslim friends to their homes for a party, for instance, should assure them that the food is halal with all sincerity, having completely understood the meaning of halal in all circumstances as explained earlier. However, some Muslims may tend to exhibit reservation and a feeling of uneasiness with the crockery or utensils used, fearing that the food, though halal, could have been cooked in utensils and served on crockery previously to cook and serve non-halal items, though these kitchen items could have been thoroughly washed with soap.
The best way to serve food to Muslims is to buy the food from Muslim stalls or caterers and serve them on disposable paper plates and cups.
The point of contention in the subject of halal food is not the non-Muslim person who cooks the food but the food itself, whether it is halal or not, and the cooking environment and kitchen utensils.
Thus, if a non-Muslim cooks in the kitchen of a Muslim home or in a “Muslim” kitchen of a restaurant, using halal ingredients, the food is halal. As an example, Muslims do eat at Hindu vegetarian restaurants. The food, like tosai, fish curry and rice, though cooked by Hindus, is free from haram (prohibited) items. Their kitchens and utensils are never used for cooking pork. They also do not use lard in their cooking. Nor do the cooks themselves consume haram items, like liquor and by-products of pork, in the kitchens.
As for a medicine which contains haram ingredients, like alcohol, a Muslim will decide whether that medicine is really necessary for the cure of the sickness or disease he has. If it is, then the medicine becomes obligatory for the Muslim to take (in contrast to facing death, which, in this case, might be synonymous with committing suicide, a sin). The logic is that the patient is not taking the medicine because of the ‘haram’ ingredient in it, like people consuming alcoholic drinks to enjoy it, but here, he is taking the mixture or tablet/capsule as a medicine in the hope of getting a cure for his ailment.
Reference: Darul Arqam Singapore