When deciding between Thai and sweet (AKA Italian) basil, there's a lot to consider in terms of appearance, aroma, and flavor. Thai basil leaves are smaller with a sturdy texture and spicier aroma, while sweet basil leaves are large and soft with a herbal, citrusy scent, and there are also numerous flavor differences between these herbs.

As with most foods, the aromas of these herbs have a lot to do with their flavor: Thai basil has a flavor that's often compared to anise, a spice made from the seeds of the anise plant, with hints of licorice and a subtle spiciness. Meanwhile, as the name implies, sweet basil is sweeter and a bit minty with a peppery note.

Thai basil is best used in Southeast Asian and Thai dishes like spring rolls, green curry, and stir-fries, while sweet basil is the classic choice for Italian dishes like pesto and pizza. You can swap these basils for each other, but sweet basil doesn't offer the same punch of flavor as Thai, and Thai doesn't meld as well with Italian flavors.