Prevention.com reports that there is some evidence that tea tree oil is effective in combating yeast infections. Everyday Health notes that although tea tree oil fights Candida in rats and in laboratory settings, no human trials have been completed as of 2014.
Everyday Health explains that some women treat their vaginal yeast infections by applying diluted tea tree oil to the area using a tampon-like applicator. Prevention.com advises using caution with this treatment, however. Introducing a possible irritant into the sensitive, already irritated vagina may be problematic and should be discontinued right away at the first sign of discomfort.
WebMD warns that tea tree is oil is for topical use only. It can cause allergic reactions, redness, itching and blisters. Tea tree oil must never be used in the eyes or taken by mouth, as rash, nausea confusion and coma are potential results.