Spearmint oil can produce a soothing or calming effect on the brain, for which it is used in aromatherapy. This oil can help reduce stress and anxiety by inducing the mind to relax. Apart from this, some other conditions in which this oil can provide relief are, asthma, sinusitis, headaches, migraine, cold, congestion, bronchitis, flatulence, nausea, diarrhea, dermatitis, and fatigue.