Xenobiotic
zee-noh-by-OT-ik
/ˌzɛnəbaɪˈɒtɪk/
Substance not naturally produced by organism.
Xerostomia
zeer-oh-STOH-mee-uh
/ˌzɪəroʊˈstoʊmiə/
Abnormal dryness of the mouth.