The McChicken is a chicken

Chicken (food)

Chicken is the most common type of poultry in the world, and is prepared as food in a wide variety of ways, varying by region and culture.- History :...

 sandwich sold by the international fast food

Fast food

Fast food is the term given to food that can be prepared and served very quickly. While any meal with low preparation time can be considered to be fast food, typically the term refers to food sold in a restaurant or store with preheated or precooked ingredients, and served to the customer in a...

 chain

Chain store

Chain stores are retail outlets that share a brand and central management, and usually have standardized business methods and practices. These characteristics also apply to chain restaurants and some service-oriented chain businesses. In retail, dining and many service categories, chain businesses...

 McDonald's

McDonald's

McDonald's Corporation is the world's largest chain of hamburger fast food restaurants, serving around 64 million customers daily in 119 countries. Headquartered in the United States, the company began in 1940 as a barbecue restaurant operated by the eponymous Richard and Maurice McDonald; in 1948...

 in many countries.
The sandwich consists of a toasted bun, breaded chicken breast meat patty, shredded lettuce

Lettuce

Lettuce is a temperate annual or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. It is eaten either raw, notably in salads, sandwiches, hamburgers, tacos, and many other dishes, or cooked, as in Chinese cuisine in which the stem becomes just as important...

, and mayonnaise

Mayonnaise

Mayonnaise, , often abbreviated as mayo, is a sauce. It is a stable emulsion of oil, egg yolk and either vinegar or lemon juice, with many options for embellishment with other herbs and spices. Lecithin in the egg yolk is the emulsifier. Mayonnaise varies in color but is often white, cream, or pale...

.
McDonald's restaurants in the south and southwestern parts of the United States serve a variant called the Hot 'n Spicy.

In certain McDonald's franchises, the sandwich was adapted to appeal to the local population's tastes.