Lavender and tea tree essential oils are traditionally considered to be mild, gentle, and safe for pediatric populations and are ubiquitous in personal care products. Recent case reports have proposed a potential association between exposure to these ingredients and endocrine disruption, but these reports contain misclassification bias. The purpose of this study is to develop a reliable and valid measurement instrument for the accurate classification of exposure to aromatic plant ingredients in personal care products to be used in epidemiological studies. This study tested the Aromatic Plant Ingredients and Child Health Survey (APICHS) for validity and reliability, contrasting it with the current approach used in clinician's offices. The APICHS was found to have exceptional sensitivity and specificity (100% and 92.86%, respectively) with a positive predictive value of 97.22%, far exceeding the sensitivity and specificity of the method currently in use. The APICHS is a valid, reliable tool for accurate classification of exposure to aromatic plant ingredients in personal care products and should be used for the avoidance of misclassification.