It is important to note that while tea tree oil is safe to be used topically, it can be toxic when ingested. Also, if you’re new to using tea tree oil, always test it out on a small patch of skin before using. This is because some individuals, especially those with sensitive skin, might experience irritation on using undiluted tea tree oil. Tea tree oil might also be unsafe for use on young children and pregnant women when used undiluted. If you’re unsure, dilute the essential oil in water or carrier oils before using. Side-effects of using tea tree oil range from mild to serious health implications. Application of tea tree oil to dry or damaged skin can cause burning and irritation. The oil can cause allergic reactions that can manifest in the form of skin inflammation, diarrhoea, nausea, etc. Avoid using undiluted tea tree oil on the scalp as it can irritate the scalp, making follicles swell and leading to hair loss.