To use aromatherapy for arthritis, you want to choose essential oils that can help calm inflammation.
Two of the top choices are peppermint and wintergreen. Add 5 to 10 drops of one of the oils to 1 teaspoon of carrier oil and rub into painful joints.
Other suggested essential oils for rheumatoid arthritis and for osteoarthritis include:
You may need to experiment to see what works best for you. Start by trying some of the blends suggested in this article.
Note: If you are new to essential oils, test each essential oil on a small area before using it on a larger area to make sure your skin is not sensitive. If you are sensitive to an oil, substitute other essential oils.
Blend the essential oils into a teaspoon of carrier oil or milk. Stir the blend into a bathtub of comfortably warm/hot water.
Bath Blend #1
You can also just soak your feet or hands in a basin of water with one drop of each of these oils.
Source: Aromatherapy for Dummies
Bath Blend #2
The same source recommends this bath blend of essential oils for gout, a specific type of arthritis caused by the formation of urate crystals in a joint (most commonly the joint at the base of the big toe):
Combine oils and add to a bath.
Make a blend using essential oils and carrier oil and massage into painful joints several times a day.
Source: Essential Oils Desk Reference
The same source recommends the following massage blend for gout:
Massage gently into affected joint 2 to 3 times a day.
Source: Healing With Aromatherapy
You can also add one tablespoon of this blend to a bath.