Is too much Peppermint toxic?
I heard that there is a toxicity level in Peppermint Essential oil. Do I need to be careful? Is too much Peppermint toxic?
As you know, toxicity is highly dependent on concentration. Oxygen is toxic at levels around 73%. There will always be and has always been some menthofuran in natural peppermint. It ranges from about 2% - 8% and is one of many components, when studied alone at high levels, could be harmful. This is not the case, however, when it is at low levels in complex natural products like peppermint oil. Attached please find the toxicity data for menthofuran. If you go to the very last section, you’ll see that the safety limit for menthofuran is 0.2mg/kg body weight per day. This is equivalent to 14mg of menthofuran per day. Since the peppermint oil contains 6% menthofuran, this means that one would need to consume 233ml of the peppermint oil per day to reach the safety limit. Furthermore, you’ll see that this safety limit is EXTREMELY conservative, since studies showed (refer to the top of the same page in the book), that more than 100 times this amount was given to rats for 14 days and no ill effects were found.