<<Disclaimer: Verify this information before applying it to your situation.>> Just to update everybody here, I received 5-6 responses. Two people stated they had contacted the company and were told the xanthan gum is grown on barley. On the side of the canister I bought it states: "Xanthan Gum is produced by the pure culture fermentation of the miroorganis, Xanthamonas campestris . . ." This got me to thinking that if yeast can be grown on a wheat/barley base, maybe this could too. One person still uses the NOW brand but the others have switched. I will choose another brand. Any suggestions? Thanks Lisa