I put a tankful of E85 into my Prius today. I just boosted my mileage by 85%! I read it should be OK to burn in a Prius and I reckon that since I'm headed overseas to find out how our oil got underneath their sand I should do my part to reduce America's reliance on oil. It seems to run the same as before, in spite of the warning on the pump that it was for "green engines" only.