Tea Tree Oil Side Effects and Warnings

When used topically, tea tree oil is thought to be safe. However, it can cause allergic inflammation of the skin.^11,13 In addition, one report suggests that a combination of lavender oil and tea tree oil applied topically caused gynecomastia (breast enlargement) in three young boys.¹⁹ The researchers who published this report also state that testing of tea tree oil revealed estrogenic (estrogen-like) and antiandrogenic (testosterone-blocking) effects. However, a literature search failed to find any other published reports that corroborate this claim.

Like other essential oils, tea tree oil can be toxic if taken orally in excessive doses. Safety in young children, pregnant or nursing women, or those with severe liver or kidney disease has not been established.