I realize this response is being posted a year after the original post, but I think this is important. I purchased some Wintergreen essential oil for use in soapmaking but have elected to not use it. It's primary esther, Methyl salicylate, is toxic. There have even been deaths reported from overuse:
From the NY Times:
"A 17 year-old cross-country runner at Notre Dame Academy on Staten Island, died April 3, 2007, after her body absorbed high levels of methyl salicylate through excessive use of topical muscle-pain relief products."
I threw my bottle of Wintergreen away. I suggest you do too.