Gluten-Free is on the menu, but the same kitchen also prepares what you avoid, so cross-contamination is possible. Tell staff what you react to, and ask how your dish is prepared before you order.
Gentle Grill is a fully vegan comfort food grill in Temecula, by its own words, with seitan sandwiches, burgers, burritos, bowls and loaded fries. It marks a few dishes gluten-free, but seitan and wheat buns are all over the menu and it does not describe its kitchen as gluten-free, so ask the staff before ordering.