Brand names should always be capitalized. (They’re proper nouns.)
Matthew drinks a lot of Mountain Dew.
Do you prefer Burger King or McDonald’s burgers?
Baby Gap is a popular store for new parents.
When Henry Ford began making cars on an assembly line, he named the brand after himself: Ford.
Some brand names have become so common that they’re used as common nouns. Be sure to capitalize them appropriately. Formal writing will require capitals for all brand names.
It would be polite to at least offer her a coke.
I think I’m going to sneeze: pass me a kleenex, please.
If you’re looking for a good brand of tissues, Kleenex may be what you want.
The mother put a bandaid on her son’s scraped knee.
Do you prefer Bandaid or Elastoplast bandages?
Capitalization: Words And Abbreviations Of Specific Names
Sometimes we have abbreviations or short forms of a brand name; these should also be capitalized.
A common soft drink is Coca-Cola.
A common soft drink is Coke.
Most people believe BMW is a good make of car.
When using a proper noun to make a new word – frequently an adjective – remember to retain the original capital of the proper noun.
Psychologists must study both Freudian and Jungian philosophies.
Mary’s new car looks kind of VW-ish, even though it’s a British car.
Do you know how to write a Sapphic verse?
Sometimes new word gets used so much it becomes a common noun and the capital is no longer required.
People are beginning to think that pasteurized milk isn’t as healthy as it sounds.
The word pasteurized comes from the last name of Louis Pasteur, the inventor of the process.
It’s annoying when people deliberately anglicize foreign words.
Anglicize is still capitalized in some places; be sure to follow local conventions.