Always be careful using essential oils. Improper use can lead to serious injury. We focus on daily home-based usage and application of essential oils. For medical issues we strongly recommend to go see a regular doctor first with, optional, additional guidance by a certified aroma-therapist. The basic directives for simple home usage;
The safest way to use essential oil is to put a few drops in a diffuser, like a candle diffuser or a ultrasonic electric diffuser, with some water.
Put a few drops of essential oil in a carrier oil, like jojoba, sesame, argan or olive oil. Avoid oils that are known to be irritating to the skin, especially the spice oils (cinnamon is known to burn the skin).
Essential oil does not dissolve in water, add a few drops of essential oil to the laundry detergent to dilute. Don't put essential oil directly on the clothes.
Essential oil does not dissolve in water. Pouring some drops into a bath is the same as putting it directly on the skin. Therefor, dilute the essential oil first in a carrier oil (sesame oil works great), in milk or in bath salt.