What is the main ingredient in tacos al pastor?

The main ingredient in tacos al pastor is pork.

The pork is thinly sliced, marinated with dried chiles, spices, vinegar, and often achiote, then stacked on a vertical spit called a trompo. As the outside browns, taqueros shave the meat into small corn tortillas and commonly add onion, cilantro, pineapple, lime, and salsa.

Al pastor developed in Mexico from the cooking traditions brought by Lebanese immigrants in the late 19th and early 20th centuries. Its method resembles shawarma and other spit-roasted meats. Lamb was common in the earlier Middle Eastern tradition, but Mexican cooks generally replaced it with pork by the 1920s and adapted the seasoning to local ingredients.

Chicken and beef can be prepared in an al pastor style, but those are variations rather than the canonical meat in tacos al pastor. The dish is also called tacos de trompo in parts of northern Mexico, while tacos árabes are a related Puebla specialty usually served in pita-like bread.