Can Frontline stain leather

Answer 1

absolutely. The darker the leather the more noticeable the stain.

Frontline like all flea and tick medications has alcohol as a carrying agent. You see, the chemistry in many commercially available pet flea medications is not friendly to leather; it can create bleaching or discoloration damage on contact. It acts like a strong solvent, stripping the color from the leather. This is most commonly seen in the form of bleaching/smearing of the leather's color on the lower front or lower back and sides; places on your furniture where the pet would rub its neck shortly after the flea medication is applied.

The damage to the leather can be from a distance as well. If your pet vigorously shakes themselves in the vicinity of leather furniture, then a significant number of tiny flea medication droplets can be sprayed across the leather, each having its damaging affect. Every place that a droplet lands can turn into bleached spot. If you see it happen, and then try to wipe the spots, you'll end up creating a bigger mess by smearing the solvent component of the medication over a broader area.

Typically it requires the assistance of a leather professional to correct.