Hey Jade, Well it pretty much depends on who you read. There's always been debate amongst the 'authorities' as to what constitutes the 'real' risks in general aromatherapy use, and if you look at roughly two schools of thought. There's the very conservative development of ATX that has evolved from the creation of aromassage by Marguerite Maury, and the subsequent adoption of the 'beauty therapy' approach in the UK where very low dosages are used, definitely not internally, and mainly on a 'relaxing', energetic, stress-relief basis. I received my first aromatherapy training in the UK, and then taught the NVQ curriculum myself in 2 colleges of Further Education there for 4 years before I came to this country. From the UK perspective then Gaultheria procumbens or G. fragrantissima, would probably still be considered a definite no-no for general aromatherapy use. The other branch however has mainly developed in Europe, primarily France and by medical physicians, so their approach is way more confident or agressive as far as which eo's may safely and effectively be used for aromatherapeutic treatments, what routes of administration are considered appropriate, and the dosages are usually much higher. You'll find references and recommendations for the considered safe and effective use of wintergreen in the works of Franchomme & Penoel, Philippe Mailhebiau, and Kurt Schnaubelt. You'll still get arguments for the more conservative approach if you read the British experts, Martin Watt and Tony Burfield for example. Having considered both sides I think Ron Guba from Australia makes a very sensible point in his article, 'Toxicity Myths - the Actual Risks of Essential Oil Use', when he mathematically works out the actual quantity of wintergreen oil that would be in reality absorbed into the body after applying to the skin in a back rub to ease those niggly aches and pains - which ends up being about the same as taking one aspirin - clearly way less than any amount that would be harmful. If you also take into consideration the fact that there are a whole bunch of over the counter products available to anyone, with anywhere between 10 and 30% methyl salicylate (which is the potentially hazardous component contained within wintergreen) - and there are no cautions to users that methyl salicylate is contraindicated for those who are taking anti-coagulant drugs such as warfarin. I know that members of the IFA (International Federation of Aromatherapists) take a vow not to use certain eo's and this is one of them - however, when you look at the math and use the eo at sensible dosage - and even if you blended only this eo at 5% in a 15 ml base, this would be much less than the levels readily available in products such as Tiger Balm for example. You're more likely to add wintergreen as only one of a # of eo's at the normally recommended safe level of 2-3% in total. Also bear in mind that you would be using your eo blend on a localized basis, and although probably frequently throughout the day, for a limited time only. All this makes a real difference to the actual risks of eo use, whilst allowing you to reap the benefits of practicall, sensible, safe and effective eo use. The only other thing I would mention is that a number of authorities warn that most wintergreen oils on the eo market are probably synthetic methyl salicylate - so you'd be wise to see if you can get some guarantee of authenticity before you buy.