anyone use horse liniment for sore muscles?

My 87 year old mother has an 86 year old "gentlemen friend" who is having back problems- i.e. sore back. She told him to use horse liniment to soothe the soreness. He ran it by his Dr., and he ok'd it. Apparently, it was used a lot when my mother was growing up, because back then they didn't have Ben Gay, or other ointments or treatments.

I have done a little research and have found that it is supposed to be safe (but not approved by the FDA) for use on humans in small amounts. The liniment should not contain DMSO- it causes blisters. Also, one should wear gloves while applying it, or wash hands thoroughly because you can have major issues if it gets into your eyes, nose or mouth. One brand name- Absormine- makes a weaker strength ointment that is designed for human use- Absormine Jr. This is supposed to be cheaper than any other brands
( i.e. Ben Gay, Icy/Hot, Tiger Balm or Biofreeze) that are designed for use by humans.

Have any of you had any experience with using this? Any input would be greatly appreciated.