Yes, looking into the hepatotoxity issue, it is not directly from Oregano oil research but from the know effects of Phenols that the oils contains. Long-term effects of 'high doses' (high generally not quantified) is then the reason for the warning.
Oregano oil when put in a carrier oil such as that used for pulling seems to generate no negative research results whatsover. 2% has been shown to have irritating effects in mice but not humans and the die-off symptoms of fungal infections (as studied) have been noted to be distinct from Oregano oil toxicity from the oil used to control the fungus/yeast (I beleive it was Candida).