Citronella essential oil is ideal for:

Aromatherapy & Headaches
Its refreshing properties make it ideal for use after a long day at work, or when the body suffers from fatigue and headaches. Add a few drops of the essential oil in a diffuser to disperse the fragrance & create a calming environment.

Skin & Hair 
Its cleansing properties control sebum production in the scalp, improve blood circulation in the veins & keep the skin clean & clear. Mix a few drops of the essential oil with your carrier oil and blend the two. Massage your skin & scalp to relieve tension & soothe sore muscles. Keep away from your eyes. 

Natural Insect Repellent
It can be used for repelling pests like mosquitoes and flies. Mix a few drops of the oil with water in a spray bottle and spray in your home.