Same with some other products that contain lanolin or petrolatum. Another one is Bag Balm, a creamy goo that was first developed to treat a cow's udders for skin damage and is now marketed as a treatment for chapped skin in people. The stuff does a fair job on leather, but it has a smell that's kind of funky.
There are other similar products called called Udder Butter and one whose name I can't remember called Moo-something-or-other that that don't smell as bad. The Moo-stuff (I have a tube of it lying around somewhere) actually smells pretty good, kind of like Jergen's Lotion with added fragrance.
Smell aside, these various creams and lotions I've tried just don't seem to give the same great results as pure lanolin, petroleum jelly or other products designed specifically for treating leather.
I'm surprised you couldn't find lanolin at your drug store. I've had pretty good success finding it, but have had to check a couple of different stores. You can also buy in on eBay. It's available in one-pound tubs that should last you quite awhile!
If you can't find pure lanolin, my suggestion would be to check some sporting goods stores, or places like Wal-Mart, for conditioners specifically for leather or baseball gloves. You shouldn't have any problem finding one with lanolin as an ingredient and you'll be getting something that you know will not be harmful to leather.
I've always wondered about "petrolatum" as I see it listed as an ingredient in many skin care products. A quick Google search discovered that it is the pure form of petroleum jelly. The petrolatum a rather thick cream that is processed into petroleum jelly to make it easier to spread and use.
There's some interesting reading here:
Petroleum Jelly on Wikipedia . Possibly everything you would ever want to know about petroleum jelly- and some stuff you probably don't want to know about!
The article lends credence to the long-held claim that PJ might tend to clog pores. Possibly, the effect on leather is different from the effect on human skin, with leather being processed and tanned and maybe having larger pores or different properties that limit the "clogging" effect.