I would argue that the blood systems in mammals is PRESSURIZED and a drop of oregano on a cut of any animal will not enter the blood..........so zero toxic effect and oregano oil not the problem in that case..................
It takes a snake type bite to enter a substance into our blood, a puncture with needle like injection.. External application of anything that has a toxic effect will be rejected by the body with acid produduction acting as a shield.
Taking 15 drops internal verses 1 drop external is not even a comparison, the LIVER will deal with that 15 drops a thouand times + more.