“Objective: To examine the effect of topically applied tea tree oil (TTO) on histamine-induced … the ears of mice.¶Methods and results: For BALB/c mice, 10 μ undiluted TTO applied immediately after, but not 30 … before intradermal injection of 600 μg histamine in 10 μl, … suppressed oedema development.”
“ TTO applied after histamine injection also suppressed histamine-induced oedema in C57/BL6 mice.”