Tea tree oil (Melaleuca alternifolia) is used as a topical treatment for various skin conditions, including dermatitis. Scientific evidence supporting its use comes primarily from its known antimicrobial and anti-inflammatory properties, which are believed to be beneficial in treating inflammatory skin disorders such as dermatitis. Several in vitro studies have demonstrated tea tree oil’s ability to inhibit the growth of bacteria and fungi commonly associated with skin infections. Additionally, some small clinical trials and case reports have suggested that topical tea tree oil can reduce symptoms of dermatitis, such as itching and inflammation, particularly in cases of seborrheic dermatitis and contact dermatitis.

For example, one double-blind randomized controlled trial found that a 5% tea tree oil gel was more effective than placebo in reducing symptoms of mild to moderate seborrheic dermatitis of the scalp. The proposed mechanisms include suppression of pro-inflammatory cytokines and reduction of microbial load on the skin.

However, the overall quality and quantity of clinical evidence remain limited. Larger-scale, high-quality studies are needed to confirm its efficacy and safety. Tea tree oil can also cause allergic reactions or skin irritation in some individuals. Therefore, while there is scientific support for its use, evidence is currently moderate and caution is advised.