Essential oils, which are more often than not, extracted from different parts of plants, are used in aromatherapy, known as an alternative medicine. These oils, also called volatile oils because of the volatile aroma they possess, contain typically the essence of a particular plant’s fragrance. The manufacture of these oils involves careful, regulated chemical processes involving complex processes like distillation, solvent and florasols extraction procedures. Essential oils can be extracted from flowers, wood, bark, leaves, roots, seeds and peel of a plant and the oil is extracted after a series of chemical processes. These oils are either applied on the skin or inhaled through nose / mouth as a process in aromatherapy. This therapy is largely used for recouping from stress, reduce physical pain, treat headaches and migraine, and improve the quality of sleep. There are many varieties of essential oils extracted from various plants. Let us take a look at them one by one. 

1. Oregano oil: It is extracted from the shoots or leaves of oregano, a plant typically grown in higher altitudes. This oil is used for improving the health of skin and is either directly applied or with the combination of coconut oil. It is known for treating respiratory issues.  

2 Frankincense oil: This oil is generally extracted from oleo-resin of the Boswellia carteri tree and are known for  treating arthritis, ulcers, rheumatism and stress. 

3 Myrrh oil: This essential oil is extracted from oleo-gum resin of the Myrrh tree secreted naturally from its trunk. This oil is considered as antimicrobial and antiseptic which is largely used in the treatment of common cold, sore throats, diarrhea and other such health issues. 

4 Thyme oil: This is extracted from the dried flower tops and leaves of the red thyme tree. The oil is majorly used for soothing nerves, aiding good blood circulation, and also to treat arthritis and rheumatism. It also helps to improve the immune system and help fight common cold and flu.

5 Lavender oil: Lavender oil is extracted from the flowering tops through distillation process. This aromatic oil is used for relaxing the nerves, relieving off muscular aches. This oil also come handy in treating minor burns on the skin. 

6 Peppermint oil: This oil is extracted from the whole peppermint plant just before flowering. It is an excellent solution to relieve stress, anxiety, sinus congestion, asthma, pneumonia, and other respiratory issues. It also helps in the secretion of bile. 

7 Turmeric oil: It is extracted from the turmeric rhizomes after the distillation process. The oil has numerous benefits as it helps cure colon cancer, neurologic disorders like Alzheimer's and Parkinson’s diseases, joint issues, and liver-related problems.

8 Black pepper oil: The oil extracted from one of the most widely used spices, the black pepper, is used for curing a  multitude of health problems. Majorly, it helps to reduce joint aches, aids digestion, used in lowering body cholesterol, and helps you deal with blood pressure. 

9 Cinnamon oil: This oil is extracted from the twigs, leaves and inner dried barks of the tree. This oil comes handy in treating respiratory issues, general body pains, arthritis, and rheumatism. This oil is also used in vaporizers, cream and lotion for better results.

10 Clove oil: Clove oil is extracted from the stem, buds and leaves of the plant. It is a good solution for treating acne, burns, cuts, and bruises. It also helps to heal mouth sore and toothaches.

12 Cardamom oil: This is oil is essentially extracted from the seeds of the unripened fruits through distillation process. This oil is a laxative and thus helps dealing with digestion issues. It also cures nausea caused by pregnancy and helps reduce heartburn.

13 Fennel oil: This sweet smelling oil is extracted from the fennel seeds through distillation process. This oil helps fight constipation and other digestion related issues. It is also used by nursing mothers for boosting breast milk. On skin, it has a cleansing and toning effect.

14 Rosemary oil: This oil is extracted from fresh flower tops via steam distillation process. This oil should never be used by a pregnant woman. It is used for treating headaches, migraines, and fatigue. It is also used for reviving sagging skin and adding glow to it.

15 Clary sage oil: This oil is extracted from leaves and flower tops of the clary sage plant. This oil can be used by women having menopause to treat palpitation, night sweat, etc. Apart from this, it helps to cure, insomnia deep seated tension. 

Thus, essential oils can be extracted from various parts of the plant and can be prepared through various processes such as distillation. Although essential oils cure a lot of health issues, they need to be carefully administered to avoid any serious side effects.