Orange oil, also known as citrus oil, is a natural and effective way to treat termites. It contains an ingredient called d-limonene which destroys the exoskeletons of termites and disrupts their nervous systems without posing risks to people or pets. Homeowners can buy orange oil products such as orange termiticides and apply them directly or hire a pest management professional to do so. However, orange oil may not be enough for large-scale infestations, in which case alternative treatments like fumigation may be necessary.