tea tree oil negative effects
If swallowed, tea tree oil can cause varying side effects ranging from drowsiness, upset stomach, vomiting, nausea and weakness, to coma, hallucinations, blood cell abnormalities, confusion and ataxia which affects muscle coordination and your ability to move voluntary muscles, states the American Cancer Society.
A single-blind study examined the use of 5% tea tree oil shampoo or placebo in 126 people with mild to moderate dandruff. After 4 weeks, the tea tree oil shampoo significantly reduced symptoms of dandruff.