It is a painless, unpleasant and subjective feeling leading to vomiting and forceful expulsion of gastric contents. 
Vomiting is voluntarily or involuntarily emptying of the stomach contents due to infection, food poisoning, overeating, excessive acidity or physiological conditions such as pregnancy (morning sickness).
Nausea and vomiting could be indicators of some underlying problem such as intestinal blockage, appendicitis, meningitis .
Usually, treatments are from grandmother's awesome prescriptions such as fennel, carom seeds, lemon juice  to enhance digestion.
The effectiveness of these herbs can be increased by using a more potent and concentrated form, which is an essential oil.
What are Essential Oils?
Essential oils are aromatic, volatile, low molecular weight extracts from flowers, leaves, roots, stems, bark, resin, and rind of fruits. Sometimes the complete plant is also used.
They are naturally extracted without any chemical modification or intermediate synthesis if otherwise, stated.
They are volatile compounds producing strong scents and are secondary metabolites by aromatic plants. 
Their chemical constituents are saturated and unsaturated hydrocarbons, alcohols, aldehydes, esters, ethers, ketones, phenols, and terpenes. 
The oils can be administered orally as gel capsule, or mixed with honey, topically as a massage oil, night and day creams, and lotions and in aromatherapy as diffusers, baths, and inhalations.
These oils provide a remedy for disease conditions; they are rejuvenating, soothing on the body and have innumerable benefits.
Essential Oils in Treating Nausea
Essential oils can be used for easing nausea because they aid in digestion and helps in the release of digestive enzymes.
Eupeptic in nature: Pepsin is a very potent digestive enzyme produced in the stomach and breaks down proteins into peptides. 
Essential oils aids in releasing pepsin. Basil, Black pepper, and spearmint oils have eupeptic action.
They are Antiemetic, which means they relieve from vomiting. Patchouli and Clove essential oils are antiemetic.
Another study showed the effectiveness of using lemon oil in inhalation aromatherapy technique to relieve nausea and vomiting during pregnancy. 
A study on breast cancer patients showed the use of massage and inhalation aromatherapy reduces the incidence of retching and nausea. 
Best Essential Oils for Nausea
Essential oils are naturally equipped with properties to enhance digestion. They are potent in enhancing the working of the body enzymes.
In this section, we have mentioned scientifically proven best essential oils and their blends to ease you whenever you have a feeling to throw up.
Basil Essential Oil
Basil essential oil is extracted from leaves of an annual tender herb.
The method employed to these dark green ovate leaves is steam distillation. It has a fresh, herbal, and penetrating aroma.
The digestive action of basil oil makes it effective oil for stomach massage which should be done clock-wise direction.
The oil must be cautiously used during pregnancy and it might irritate the skin in some person.
Cardamom Essential Oil
Cardamom essential oil is steam distilled from seeds of a perennial reed-like shrub. It has a warm, sweet and spicy undertone and has a pale yellow tinge.
The oil is useful in stimulating appetite, thereby, enhancing digestion and deals effectively with nausea. 
It has the ability to encourage the flow of saliva.
Lavender Essential Oil
Lavender is an aromatic green woody shrub. The oil is extracted from flowering tops. It has a sweet, floral aroma. The oil is rich in therapeutic properties.
The medicinal properties of the oil have known benefits in treating vomiting. 
People with low blood pressure, sensitivity, or pregnant women must use oil cautiously.
Coriander (seed) Essential Oil
The oil is extracted by crushing ripe coriander seeds of a strongly aromatic herb.
It has bright green delicate leaves that are used for garnishing in many curries. The leaves are extensively used for flavoring purposes in food
The oil is mainly used for curing digestive complaints, in fact in Chinese medicines it is prominently used to treat nausea.
The oil is beneficial for improving the function of the alimentary canal
Fennel Essential Oil
Fennel essential oil is extracted from crushed seeds of fennel.
The plant has leathery leaves and yellow flowers. It has a sweet, earthy and peppery aroma.
The oil is stomachic thus imparting appetite and improving digestion properties of the stomach. It is a tonic for the digestive system.
In a human trial, of a 2012 study, it was reported that using a blend of Aniseed oil, Fennel oil, Roman Chamomile oil, and peppermint oil alleviated postoperative nausea in people. 
A study reported using a blend of Fennel, Roman Chamomile, and Peppermint in massage or abdominal compress, diffuser reduced nausea symptoms in patients of palliative care facility. 
The oil is contraindicated to be used by cancer patients or pregnant women. A person with seizures must use it cautiously.
Ginger Essential Oil
Ginger essential oil is extracted from dried ground root or rhizome root. The oil is pungent, fresh, and spicy-sweet.
A study trial reported 80% of patients taking inhalation of 5% ginger oil before surgery showed no symptoms of postoperative nausea and vomiting (PONV). 
Another study used an undiluted mixture of ginger, cardamom, and tarragon essential oil on the neck of patients after surgery, results showed a significant block of nausea and vomiting within 30 minutes of application. 
The oil is beneficial during travel sickness and vomiting. 
Peppermint Essential Oil
Peppermint Essential oil is extracted from a flowering herb.
The aroma is mint-like, penetrating and full of freshness. This oil is extracted from leaves and has a pale yellow colour.
A study used 4 drops of pure mint oil in a bowl of water (diffusion aromatherapy) during the entire night, and the severity and intensity of nausea decreased for intervention group while increased for the control group.
A study showed inhalation vapor of this oil not only reduced the severity and incidence of nausea and vomiting but also decreased antiemetic requirements. 
The oil must not be used on lactating mothers or infants and preschoolers.
Spearmint Essential Oil
Spearmint essential oil is steam distilled from flowering tops and wrinkled, spiked leaves of the plant. It belongs to the mint family and has a refreshing, rejuvenating flavor.
It is rich in eupeptic action and is an efficacious tonic for the digestive system. The oil increases bile production in the stomach and aids in digestion.
It can mitigate some effects of travel and seasickness or nausea.
The oil is contraindicated for use on babies and pregnant women.
Rose Essential Oil
Rose essential oil is extracted from rose petals having a deep, rich, sweet scent.
The oil has numerous benefits including regulation of appetite and stomachic and has a reddish-orange tinge.
It plays an important role in the digestive system and strengthens the stomach, promotes the flow of bile and the elimination of feces and useful for nausea.
People with skin sensitivity, pregnant women, and children below age two must use the oil cautiously.
Rose Wood Essential Oil
Rosewood essential oil is steam distilled from wood chips of a medium-sized tropical tree having reddish bark and heartwood. It has a sweet, floral aroma and a pale yellow tinge.
The oil has cephalic properties having the potential to relieve headache accompanied by nausea.
Precautions While Using Essential Oils
Since these oils are very concentrated, so always dilute them before using.
Always perform a patch test on the inside of the arm before using the oil to test for photosensitivity and allergic reactions.
Avoid their contact from genitals, mucous membranes, inner ear, eyes. In case of contact irrigate eyes with milk or vegetable oil quickly or massage with it.
The oils must be stored in tightly capped bottles in dark and away from heat since they are flammable.
People with allergies, sensitive skin should cautiously use them; pregnant women and children below 5 years should avoid their use.
Avoid sun exposure for at least 6 hours after use.
Nausea can happen to anyone and at any point in time. The uneasiness, giddy feeling is disturbing and hampers the daily activities of a person.
Here, Essential oils come to rescue!
Essential oils are very useful in solving digestive problems. They help in secretion of pepsin in stomach and bile juice to aid digestion.
Also, they are tonic for the digestive tract and helps in complete elimination.
So next time you feel a roller coaster in your tummy and want to puke, you know the essential oil blends to use that will appease your stomach and make it feel good again.