Question: "What does the Bible say about aromatherapy?"
Answer: Aromatherapy is a branch of alternative medicine that uses plant extracts, especially those with odor, to treat medical and psychological ailments. Despite the name, these extracts (also known as "essential oils") can either be administered by inhalation or applied directly to the skin. Aromatherapy is used to treat skin conditions, congestion, and infection. Essential oils like lavender are also used to aid relaxation. Besides the effective use of peppermint in freshening breath, there is no scientific evidence that aromatherapy actually has a medical benefit, and many essential oils can be dangerous if administered incorrectly.
The Bible mentions aroma and incense extensively. In Exodus 30:22-33, God instructs the Israelites to make anointing oil with myrrh, fragrant cane, cinnamon, and cassia (similar to cinnamon) in a medium of olive oil. The next passage describes the incense to be used in the tabernacle and, later, the temple, including spices, onycha, galbanum, and frankincense. Frankincense was also to be added to the grain offering (Leviticus 2:1-2) as a "soothing aroma to the LORD." The wise men brought frankincense and myrrh to the young Jesus (Matthew 2:11), and Mary washed Jesus' feet in nard, an extremely costly ointment, "and the house was filled with the fragrance of the perfume" (John 12:3).
In the time of the Old Testament, plant-based medication was viewed with ambivalence. Its use was so closely linked with pagan religious practices that it wasn't encouraged by Scripture. Instead, the Israelites were to rely on God as their Healer (Exodus 15:26; Jeremiah 46:11). Priests were authorized to identify ailments but not to treat them (Leviticus 13:7, 19, 49). The anointing oil prescribed in Exodus 30 was used to dedicate people and things for God's service. Frankincense and myrrh were used in embalming. And, while nard may have a pleasant aroma, there is nothing to indicate a medical benefit to Jesus' feet beyond deodorizing.
Using plant-based extracts for topical and respiratory medication is not intrinsically New Age, even though at times it can be combined with unbiblical practices. Although care should be taken when using essential oils (especially around those with allergies), there is nothing unscriptural about using scents or plant oils to treat medical conditions.