I've used rescue remedy before, I've heard some people say they think it makes them worse?We have a herbal (I think) calming thing called rescue remedy, not sure if you can find it but it works really well. We have given it to Fanta a few times for car trips, it helped her relax in the car, it might help Tucker depending on why he is car sick
Best results I've had for car trips, for my majorly anxious dog, was with a thundershirt. She doesn't travel much though cause I don't find the stress worth it, we only go to vet visits.