For aromatherapy use. For all other uses, carefully dilute with carrier oil prior to use. Please consult an essential oil book or other professional reference source for suggested dilution ratios.
A few drops can be mixed with carrier oils to make a great aromatherapy massage oil.
Rosemary oil can be diffused for aromatherapy. It blends well with essential oils like Frankincense, Lavender, Clary Sage, Basil, Thyme, Lemongrass, Roman Chamomile, Peppermint, etc.