Data Views Plants (>= 1 Chemical): 17 All Chemicals: 2 CSV Excel PDF Click on column headings to sort table by that column Chemical Dosage References AZELAIC-ACID --* HYDROQUINONE --Martindale's 29th *Unless otherwise noted all references are to Duke, James A. 1992. Handbook of phytochemical constituents of GRAS herbs and other economic plants. Boca Raton, FL. CRC Press.