Cabbage is the predominant filling in modern American egg rolls.
Despite the name, American egg rolls generally do not contain egg as their principal filling. Their characteristic interior is usually shredded cabbage, often combined with pork, shrimp, chicken, carrots, bean sprouts, onions, or other vegetables. The filling is enclosed in a relatively thick wheat-flour wrapper and deep-fried.
The modern American style developed in Chinese-American restaurant culture, especially in New York City during the early 20th century. Older recipes did not always use cabbage, but cabbage became the defining flavor and bulk ingredient in the version widely served today.
The origin of the word egg remains uncertain. One theory connects the Chinese word for egg with the word for spring, while another suggests that early Chinese-American cooks used egg in a wrapper or in an older recipe. Some versions brush the wrapper with egg white to seal it, but that does not make egg the predominant filling.