Nutmeg and mace are two spices derived from the same plant, the nutmeg tree (Myristica fragrans). The nutmeg tree is indigenous to the Banda Islands of Indonesia but is also grown in the Caribbean (e.g., Grenada). Several commercial products are produced from the nutmeg tree, nutmeg and mace being the best known. Nutmeg is the actual seed of the tree, roughly egg-shaped and about an inch long, while mace is the dried "lacy", reddish covering of the seed.
Other products include their essential oils. Other nutmeg tree species include the M. argentea which produces 'Papuan' nutmegs from Papua (Indonesia) and Papua New Guinea, and M. malabarica which produces 'Bombay' nutmegs from India; both are used as adulterants of M. fragrans products.
The spices in their ground form are mainly used in the food processing industry, principally in the seasoning of meat products; they are also used in soups, sauces, baked goods and spice mixes such as curry powder in Japan. Both spices have similar taste qualities; mace is more popular in light coloured foods because of its light orange colour. Mace (edited from "Nutmeg"), in general, tends to be sweeter and more delicate.
The essential oil is obtained by the steam distillation of ground nutmeg. The oil is colourless or light yellow and smells and tastes of nutmeg. Essential nutmeg oil as such is used as natural food flavouring in baked goods, syrups, beverages (e.g., cola), sweets, etc. It replaces ground nutmeg as it leaves no particles in the food.
Nutmeg is extremely toxic when injected intravenously. Excessive consumption of the spice is also dangerous and can lead to death. Nutmeg can also cause hallucinations when taken in excess, along with nausea, dehydration, and generalised body pain.