Oregano is well known as the "pizza herb", and is widely used in Mexican and Italian cookery. Both fresh and dried material can be used. The dried herb is also used in many other processed foods such as alcoholic beverages, meat and meat products, condiments and relishes, snack foods and milk products.

Origanum oil is used as a food flavor and also as a fragrance component in soaps, detergents and perfumes. The major source of the oil is from T. capitatus and Origanum species rich in carvacrol, a phenolic constituent of the oil. Carvacrol has antifungal and anthelmintic activities, although weaker than those of thymol, a chemically-similar phenol found in thyme. 

Oregano is a condicio sine qua non in Italian cuisine, where it is used for tomato sauces, fried vegetables and grilled meat. Together with basil, it makes up for the character of Italian dishes.

The dish most associated with oregano is pizza. Bread of this kind was eaten in Southern Italy for centuries; according to the legend, pizza came into existence in 1889, when King Umberto and his wife Margherita sojourned in Napoli (Naples). Pizza, at this time not more than white bread flavored with tomato paste, was then a popular food for the poor masses. To honor the Queen, a local baker devised a richer kind of pizza: In addition to the red tomato paste, white mozzarella cheese and green basil leaves were employed, thus reflecting the colors of the Italian flag. This invention became known as pizza Margherita and spread all over Italy and, with some delay, over the rest of the world. 

Today's pizza rely more on oregano than on basil, and use a multitude of further ingredients: Ham, sausage, fish, shellfish, mushrooms, artichokes, onion, garlic, olives, capers, anchovies and more make pizza a sophisticated delicacy, although it had once been the poor man's sandwich. 

Oregano can effectively be combined with pickled olives and capers or lovage leaves; other than most Italian herbs, oregano harmonizes even with hot and spicy food, as is popular in Southern Italy. The cuisines of other Mediterranean countries make less use of it, but it is of some importance for Spanish, French and Greek cooking.

Store fresh oregano in the refrigerator, wrapped in paper towels and enclosed in a plastic bag. Dried oregano, found with other seasonings in all supermarkets, should be stored away from light, heat, and moisture for up to 1 year; crush in the palm of the hand to release its flavor.

To chop or mince fresh oregano: Holding the stems, gather the leaves into a tight, compact bunch. Using a chef's knife, cut across the bunch to chop the leaves coarsely. Discard the stems. To mince, gather the chopped leaves. Steadying the top of the blade, rock the knife in an arc until desired fineness is reached.