Breathing in peppermint oil can have multiple health benefits. The aroma of peppermint oil has been shown to effectively reduce feelings of nausea and improve mental focus and alertness. It also has decongestant properties, making it useful for opening up airways and relieving sinus congestion. However, it's important to use caution when inhaling any essential oils, as they are highly concentrated and can be irritating to the eyes and mucous membranes if used improperly.