The medicinal parts of the plant are its flowers and leaves. One of the most popular essential oils available, Lavender oil is used to treat a wide variety of ailments and can be a vital component of any household first-aid kit. Externally, the oil may also be used to soothe and promote natural sleep and as a stimulating liniment to help ease the aches and pains of rheumatism. Less potent than the essential oil, the flowers possess those properties that are useful for fighting nervous exhaustion, stress, tension headaches, anxiety, colic, indigestion, and halitosis, among others. Lavender is readily available as liquid extract or essential oil, tea, tinctures, fresh or dried leaves and flowers, and in herbal formulations.
Lavender combines well with rosemary, kola, skullcap, valerian, lady's slipper, and chamomile.
The essential oil should not be taken internally but can be inhaled, rubbed on the skin, or used in baths. Do not apply lavender oil near the eyes. Avoid high doses of the herb during pregnancy because it is a uterine stimulant. These are traditionally served at Passover, when flourless desserts are the rule. The meringue can be very sensitive to humidity, so it is best not to make them on a damp day.