Oregano, scientific name Origanum vulgare, is a perennial herb in the mint family (Lamiaceae). It is native to temperate western and southwestern Eurasia as well as the Mediterranean, but it is now cultivated all over the world. Oregano has purple flowers and spade-shaped, olive green leaves; it’s a perennial and can survive mild winters.
As a spice, oregano is used for its earthy, mild flavor. Since it is just dried herbaceous material, there isn’t much appreciable macro-nutrition, but dried oregano is actually a great source of polyphenols (2319 mg per 100g)! As an essential oil, oregano is so strong that it can numb the tongue and is used as an antimicrobial by some people attempting to fight off colds.
Getting your spices from a reliable source is incredibly important, because the small differences add up when you’re talking about difference in quality (and then add multiple spices per dish!).