Tea tree oil is an all-natural essential oil that's extracted from the leaves of the Australian Melaleuca tree. Because tea tree oil is naturally antibacterial, antifungal and antiseptic, it's commonly used in cosmetics and skincare, but it's also a great household cleaner when mixed with water. It's so concentrated that all you need is a few drops to create an effective cleaner. Use it in everyday applications like cleaning countertops and tile. It's also great for disinfecting areas where pets have had accidents or kids have gotten sick.