Plants possess a wealth of different chemical ingredients, ranging from substances with simple structures to very complicated ones, such as terpene or benzoic derivatives. Some are poisonous, others are important raw materials in biochemistry and medicines, while still others are responsible for the appetizing odors we identify with certain foods.

Although the majority of spices are derived from plants, the most important spice is a mineral. Salt has been mined for culinary use (and perhaps, more importantly, as a food preservative) for more than 2,500 years, as well as secured at the seaside by the evaporation of seawater. Saltwater creatures, such as small herrings or other salty-tasting fish, have also been used as spices.

Among the spices of plant origin are such widely used spice plants as pepper and ginger. Other plants are frequently regarded as a flavoring, such as onions, peppers, carrots, and celery. Moreover, there are herbs, such as dandelions and daisies, which in the past were used as spices, as can be seen in old recipes. Although not normally considered to be spices, certain fruits and nuts, such as rowanberry, cranberry, and hazelnut, are also occasionally recommended in recipes as flavorings. In addition, plant stems, flowers, seeds, fruits, leaves, roots, and even pollen grains have been employed as spices.

Although all spices do not necessarily figure significantly in nutrition, there are other sound reasons for cooking with them, not the least of which are the aromatic ingredients they contain that can influence the taste of food. But spices also have chemical ingredients that aid digestion and play a role in food conservation (as does salt) by inhibiting bacterial growth and rendering the food unpalatable for microbes and insects. Until relatively recently, most spices had been luxury items, and their usage was an indicator of well-established culinary traditions within a relatively longstanding (and presumably highly developed) culture (Stobart 1977; Küster 1987).