你是不是认为精油对皮肤完全无害?

Essential oils may be natural, but that doesn't mean they're always healthy or good for you. They're extremely concentrated versions of chemicals that plants make for various reasons: some to attract pollinators, some to repel or harm their natural enemies.
精油可能是天然产品，但这并不意味着精油一定是健康的、有益的。植物因各种原因（吸引传粉昆虫、击败或伤害它们的天敌）产生化学物，而精油就是这些化学物的浓缩产物。

These oils' utility to humans is mainly that they smell good, which you've probably already figured out: essential oils don't cure cancer and there's no solid evidence they do much of anything else for health.
人们使用精油主要是因为味道好闻，我猜你可能已经想到了：精油不能治愈癌症，而且尚未有证据明确表明它对健康有益。

But people who love (or sell) essential oils will often say there's an oil for everything, and they can be used in a variety of ways. Meanwhile, the Atlanta Institute for Aromatherapy has been collecting examples of people who were harmed by essential oils, in an effort to convince aromatherapy professionals that these things are not harmless.
但喜欢或销售精油的人总会说精油是万能的，涂抹的方式也多种多样。同时，亚特兰大芳香疗法研究所一直在收集那些被精油所伤的人的例子，以让芳香疗法专业人员信服：这些精油是无害的。

Reading through their injury report, people have said they got skin irritation, burns, and worse from using oils in a variety of harmless-sounding ways. One woman got blisters on her back after putting a few drops of sweet orange oil in their bath water. Another diluted some frankincense, marjoram, and lemongrass oils and applied the mixture behind the ears, where it seemed to cause welts and burning.
翻阅这些人的受伤报告，我们发现：他们的描述基本都是用各种各样听似无害的方式涂抹了精油，但他们的皮肤却受到了刺激、灼伤，甚至更为糟糕。一位女士在泡澡水中滴入几滴甜橙油之后，她的背上出了水泡。另一位女士将乳香油、马郁兰油和柠檬草油稀释，而后将这一混合物涂抹在耳朵背后，结果却引起灼伤和疤痕。

Some oils, especially citrus ones, can cause burns and blisters by sensitizing skin to the sun. Others can irritate skin directly. The advice to dilute oils, either in water or in a "carrier" oil such as coconut oil, doesn't always help, as the injury reports show. Saddest of all are the stories of people who applied oils to their skin, or their children's skin, as a treatment for a skin condition, only to find the oils made the condition worse. (There's a photo here, for those of you who are curious about that sort of thing.)
有些精油，尤其是柑橘类精油，会使皮肤在阳光下变得敏感，从而引起灼伤和水泡。其他人的皮肤则直接受到了刺激。受伤报告表明：在水中或椰子油等"载体"油中稀释精油的建议并不总是管用的。最惨的是那些将精油直接涂抹到自己肌肤或孩子肌肤上的人，虽然他们涂抹精油的本意是治疗皮肤病，但最后得到的结果却是皮肤病的症状更为严重。（如果你们对这种事很好奇，我这儿有照片为证。）

Bottom line, some oils may be safe for skin, when appropriately diluted, but don't trust a friend or an oil salesperson to give you the right parameters for that. (Some of the injuries in the report resulted from using a product exactly as directed.)
最重要的是，有些精油在适当稀释之后可能对皮肤无害，但如果你的朋友或销售给了你一份正确使用指南，千万别信。（报告中，有些人就是因为按照指示使用了产品才受的伤。）