What it is, what it does
Several different plants are called oregano - they are united by a similar savoury pungency and a high content of carvacrol, an antioxidant that gives the plants their characteristic taste and fragrance. Oreganos are particularly high in antioxidants, which doctors believe may explain the low incidence of heart disease in Greece, where the local variety rigani is used prolifically in cooking.

In the kitchen
The quintessential herb for pizza, oregano lifts tomato sauces and lamb in particular but suits a wide range of Italian meat, poultry and fish dishes. It's also a good to keep on hand for Cajun, Mexican and Mediterranean cooking, and works well with cheese and eggs. Crush dried oregano lightly in your hands before adding to dishes to activate its essential oils, and for the best taste add it near the end of cooking.

Varieties
Origanum vulgare or 'Greek' oregano is the most common variety and some believe it tastes best. Italian oregano is a cross between marjoram and Greek oregano. Mexican oregano is a different plant - poliomintha longiflora. Marjoram is a close relative of oregano but has a gentler, sweeter flavour.