Oregano is an herb composed of the fresh or dried leaves of the oregano plant. The plant has tiny leaves that lend a pungent aroma and strong flavor to a variety of savory foods. Basil is a wonderfully fragrant herb that is especially popular in Italian cooking. It is added to the majority of tomato-based sauces for pasta offering a sweet and pungent flavour and is also one of the main ingredients of the olive oil and herb pasta sauce pesto.