p-Menthane-3,8-diol, also known as para-menthane-3,8-diol, PMD, or menthoglycol, is an active ingredient used in insect repellents. It smells similar to menthol and has a cooling feel. There are eight possible isomers of p-Menthane-3,8-diol, and the exact composition is rarely specified and is commonly assumed to be a complex mixture.
Refined OLE contains approximately 64% p-Menthane-3,8-diol (a mixture of the cis and trans isomers of p-menthane-3,8-diol). OLE has been notified under the European Biocidal Products Directive (BPD) 98/8/EC (now BPR Regulation (EU) No. 528/212) under its generic name "p-Menthane-3,8-diol rich botanic oil" and is currently proceeding through the registration process with the Health and Safety Executive in the UK. It is also registered with Canada's Pest Management Regulatory Agency under the generic name "p-Menthane-3,8-diol and related oil of lemon eucalyptus compounds".