Tim Cook answered
Ichthammol ointment is a drawing balm, with the chemical name ammonium bituminosulfonate, a naturally occurring compound produced as a side effect of oil shale manufacture.
Ichthammol ointment, sometimes sold as ichthyol, is available in most pharmacies, or online stockists such as cvs.com (where it has won rave reviews) and esbropharmacy.com. Be warned, it can be messy to apply, and has quite a strong smell of bitumen, but it is effective.
If in any doubt over using Ichthammol ointment, please ask your pharmacist for advice first.
For more blurtit answers on this topic, go to Where Can I Buy Ichthammol Ointment? or Where Can I Buy Ichthammol Ointment In The UK?