5/5 Oolong Tea's Health Promotion Benefits Other Effects ・Oolong tea is effective in preventing tooth decay and atopic dermatitis. According to the Department of Dentistry, Osaka University, consuming polyphenol found in oolong tea contributes to the reduction of tooth decay significantly and is effective in preventing the occurrence of such decay. The Department of Dermatology, Shiga University of Medical Science carried out research into its effect on atopic dermatitis and discovered that 64% of sufferers of atopic dermatitis reported an improvement in their skin condition. This indicates that oolong tea is very effective regarding atopic dermatitis.