Although khaki bush can be harvested from the veld and provides an income to collectors, it is also grown commercially in South Africa, France and North America for its essential oil. The oil has a wild-citrus-like smell and has a yellowish to reddish amber colour.

Highland Essential Oils on the farm Vlakbult (near Clocolan) cultivate around 500 ha of Tagetes (about half of their production need) annually, for an output of about 1 ton of oil.

Leaves, stalks and flowers are picked when plants are in seed, mechanically chopped and the oil is then steam-distilled. Initially the oil has a wild unpleasant smell, but after 12 months of maturity, it achieves a pleasant sweet-fruity (mango-like) smell and attains a stable composition. During maturation, the oil thickens and the colour darkens. The aroma of the oil develops further in the following 5 years, after which the oil quality deteriorates.

Although Tagetes Oil is not a popular fragrance oil, it is used in some perfumes. It can be blended with massage oil or used in the bath where it can assist with wounds, cuts, coughs, chest infections, parasitic and fungal infestations.

The oil is very effectively used for wounds and a wide variety of infections.

The boiled leaves of the Tagetes minuta are used to treat infections in the respiratory system or stomach problems, by drinking the boiled mixture. In a 5% dilution, Tagetes Oil has been used to kill maggots in open wounds. When used in a cream or lotion, it can have a beneficial effect on fungal and microbial infections and especially helpful when treating weeping wounds or athletes foot.

In burners, vaporizers or steamers, the vapour from the leaves can treat headaches, coughs, bronchitis, chest infections or be an insect repellent for a wide variety of insects. The vapour also acts as an antiseptic in a room.

The leaves and flowers are a good insect repellent and are often seen hanging in dwellings to deter swarms of flies and mosquitoes. The oil is also used as a repellent to the bowfly and is useful as a bowfly dressing.

Caution should be taken when using Tagetes Oil. It is very powerful and should be used sparingly on the skin (less than 0.5% dilution), not used on a sensitive skin, and avoided during pregnancy. It is photo toxic and may cause photosensitivity.

Several other species of Tagetes, commonly known as marigolds with their rich and vibrant orange, yellow and brownish colours, are very popular as garden plants and in many cultures it plays an important role in traditional ceremonies. In Mexico, it is regarded as a flower of the dead during the 1st November celebrations of the Day of the Dead, where they use it to honor the lives of the family and friends who have passed away. It is believed that its strong odour attracts dead souls towards the flowers, therefore burial sites are adorned with marigolds. It was used by the Aztecs in many religious ceremonies and also as a medicine. In India, it is widely cultivated to make garlands, for decorative purpose in marriages and festivals.