I know exactly what you mean. Nikko is the same way. He won't last more than 10 minutes before he is vomiting and gagging.
I have tried many things and nothing really seems to work for him but maybe they'll work for you. Try not to feed him before you go out so the food won't upset his stomach. Some have said ginger helps calm the stomach so you can give him a ginger tablet (I have searched for the tablets but around here they only have the caplets and I heard they were no good). Instead you can try to feed him ginger snaps to see if they help settle his tummy. I also tried an herbal remedy for anxiety that I bought from the pet store. They are these drops that you give him and supposedly they help calm him down. I must say, when I gave these to Nikko, he lasted a little longer without throwing up so you might want to try them. They are called Homeopet Travel Anxiety and you can order them online or at any pet store. Lastly, I have also tried taking his favorite toy and trying to distract him while in the car. If you make it a fun, positive experience, maybe he will look forward to the ride. I wish you the best of luck and I hope others on here have better advice for you.
