The oils do produce a definite Physiological effect and should be used with respect. Storing essential oils Essential oils should be stored in a cool, dark place. Many oils are sensitive to Ultra Violet light and should be stored in dark glass bottles.
Some oils are toxic if swallowed neat.
Essential oils should never be stored in plastic bottles. The oils should not be stored with the droppers in place as the vapors may corrode the dropper. If stored properly essential oils will keep for about 1 year. Some citrus oils, eg lemon, orange and lime will not keep for as long. Every persons sensitivity to oils can vary considerably.