Yes, patchouli oil can be used in a bath as part of an aromatic ritual, where its warm, woody profile is known to create a grounding effect. To use it safely and effectively, you must first disperse the oil. Pure essential oils do not mix with water and can concentrate on the skin's surface, potentially causing irritation.
The safest method is to dilute 3-5 drops of patchouli oil into a tablespoon of a dispersing agent before adding it to the bathwater. Suitable dispersants include full-fat milk, plain honey, or a neutral, unscented bath gel base. Stir this mixture thoroughly into the running bath water to help it disperse. Alternatively, you can dilute the oil in a carrier oil (like sweet almond or olive oil) if you are also seeking a skin-softening effect. Soak for 15-20 minutes to allow the aroma to develop, which, as noted, is persistent and develops gradually, aiding the transition to a quieter state. Never add undiluted essential oil directly to bath water. Always exit the bath carefully as oils can make surfaces slippery.