Purpose: This study aims to investigate whether shampoo containing tea tree essential oil is effective in improving problematic scalp. Methodology: Nine adult men and women with sensitive scalp were used once a day for 28 days by mixing sensitive shampoo and tea tree essential oil in a 9:1 ratio. Areas where inflammation and erythema appeared after use of the product were regularly used by scalp experts as scalp diagnostic devices to diagnose improvement. The Likert 5-point scale was applied to the satisfaction of improving the sensitive scalp of the subjects. Results: Inflammation was the highest after the experiment, followed by erythema, scalp overall improvement, cleanliness, itching, and heat sensitivity. Among them, inflammation and erythema showed t=2.87 (p=0.021) and t=3.00 (p=0.017), respectively, confirming that tea tree essential oil significantly improved sensitive scalp condition. Conclusions: Therefore,Shampoo products with tea tree essential oils have been shown to be very effective in improving erythema and inflammation of sensitive scalp.