My last post on lip balm brought to mind the morning I woke up with Pamela Anderson's lips. I also had a large hive on my left cheek and my left eye was swollen shut. The next day my lips went black and the skin fell off - as if they had been blow-torched.

Feeling remarkably sorry for myself (and not a little self-conscious), I want to see Hari at my local pharmacy (Gideon's on Broadway; once you've tried it you'll never go to Duane Read again) and, unruffled as always, he handed me a tube of Aquaphor. I was back to normal (lips like Zoe Wannamaker's) within 24 hours.

Acquaphor worked so well that I've always been too scared to see what was in it. Truth In Aging doesn't let sleeping dogs lie, however, and courage was rewarded by a pleasant surprise. Acquaphor contains mineral oil, cerasin (a mineral alternative to beeswax for those with sensitive skin), lanolin, pathenol (provitamin B5) and chamomile (an anti-inflammatory).

Then I looked again. Damn. That's the inactive ingredients list. The active ingredient is petrolatum (41%). I must confess to being perplexed as to whether petrolatum is really something to avoid. In America, it seems to be in everything, including my beloved Elizabeth Arden Eight Hour Cream. In Europe, it used to be in everything and then in 2003 it became a blacklisted ingredient. As far as I can work out, certain impurities may be in the petrolatum and they can cause allergies and even be a carcinogen. Cosmetics should use highly refined petroleum that has been cleaned of these impurities. The EU requires product makers to provide a certificate saying the petroleum used is carcinogen-free.

This should mean that a petrolatum-based product bought in Europe is safe. In the US, where there isn't such a restriction, we frankly don't know. So, it is probably best to avoid it if possible. But if you find something that works and that you don't get a reaction to, then there is probably no need panic and go petroleum-free.

For those of you who like loose ends to be tied, the cause of my Pammie Anderson lips was an allergic reaction to a toothpaste by Tom's of Maine.