Cosmeticsinfo.org is an information Web site that includes factual, scientific information on ingredients most commonly used in cosmetics and personal care products in the United States. The Personal Care Products Council, an industry trade group, sponsor this Web site. Good for ingredient uses and properties -- not so much for toxicity information.

Site offers easy to read info about ingredient uses and some toxicological information. NOTE: the site is affiliated with cosmetic manufacturers and promotes their products. Consider the bias when using this site.

Excellent source for anyone exploring "essential oils." From the publisher: The Encyclopedia of Herbs and Spices provides comprehensive coverage of the taxonomy, botany, chemistry, functional properties, medicinal uses, culinary uses and safety issues relating to over 250 species of herbs and spices. ... many are traded globally and are indispensable for pharmaceuticals, flavouring foods and beverages, and in the perfumery and cosmetic industries.

Hawley's Condensed Chemical Dictionary is a compilation of technical data and descriptive information covering thousands of chemicals and chemical phenomena, trade name products, processes, reactions, products, and related terminology. Provides concise, condensed, and prompt definitions of terms and phenomena in chemistry, biology, biochemistry, and more. ~from the publisher.

The popular crowd-sourced, free encyclopedia is a good starting place for academic research.