Spices are available in the form of leaves, Seeds, flowers, or stems from plants used for flavoring or as a garnish. These spices, sometimes may be ground into a powder for convenience.

As they tend to have strong flavors and are used in small quantities, spices tend to add few calories to food, even though many spices, especially those made from seeds, contain high portions of fat, protein, and carbohydrate by weight. Many spices, however, can contribute significant portions of micronutrients to the diet.

When used in larger quantity, spices can also contribute a substantial amount of minerals, including iron, magnesium, calcium, and many others, to the diet.
Most herbs and spices have substantial antioxidant activity, owing primarily to phenolic compounds, especially flavonoids, which influence nutrition through many pathways, including affecting the absorption of other nutrients.

Many spices have antimicrobial properties. This may explain why spices are more commonly used in warmer climates, which have more infectious diseases. Spices are sometimes used in medicine, religious rituals, cosmetics or perfume production.