TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Formulation: The formulation further comprises an emulsifier. The formulation comprises lemongrass oil, citronella oil, tea tree oil, lavender oil, mandarin peel tincture, apple vinegar and Tween; further comprises additional ingredients having an insect repelling activity; and further comprises a carrier. Preferred Components: The essential oils are selected from lemongrass oil, citronella oil, eucalyptus oil, tea tree oil, lavender oil, geranium oil, clove oil, Cajeput oil and Lemon balm oil. The volume/volume concentration of each of the essential oils in the formulation is 0.1-3 (preferably 0.5-2)%. The citrus peel tincture is mandarin tincture. The volume/volume concentration of the citrus tincture in the formulation is 0.1-1 (preferably 0.5)%. The vinegar is apple vinegar. The volume/volume concentration of the vinegar in the formulation is 1-10 (preferably 4-6, especially 5)%. The emulsifier is Tween 20 (RTM: emulsifier) or Paraffin oil. The concentration (volume/volume) of the emulsifier in the formulation is 0.1-1 (preferably 0.5)%. The carrier provides the form of a solid, liquid, powder or foam. The carrier is suitable for distribution of the formulation through spraying, spreading, coating, dripping, dissolving or sprinkling. ACTIVITY - Insect Repellent. A formulation comprising tea tree, lemongrass, citronella and lavender oils, mandarin peel tincture and apple vinegar, was prepared, and tested for insect repellency time and repelling quality. The repelling quality was measured on 1-10 scale where 1 was hardly any protection and 10 represented total protection. The formulation showed repelling quality of 10 for repellency time of 360-480 minutes.    MECHANISM OF ACTION - None given.    ADMINISTRATION - The formulation in the form of solid, liquid, powder or foam is distributed through spraying, spreading, coating, dripping, dissolving or sprinkling (claimed). No dosage details given.    EXAMPLE - An insect repellent aqueous formulation comprising (vol./vol.%): tea tree oil (1), lemongrass oil (0.5), citronella oil (2), lavender oil (0.5), mandarin peel tincture (0.5), apple vinegar (5), Tween 20 (RTM: emulsifier) (0.5) and water (90), was prepared.