I have the same issue, although not actual vomiting, but misery and nausea in the car. Here is something that helped me:
Car Sickness (Dog)
If your dog is miserable from a ride in the car, here are a few suggestions
1. One of the best herbs for nausea of any kind is ginger - be it a couple of ginger snap cookies ginger ale/beer, crystallized ginger, or a 500 mg capsule of the powder. Just give it about 30 minutes before any car trip. Good for people, too. Even for seasickness.Try powdered ginger root capsules. Ginger root does help calm the stomach. Ginger can be given in tea, too, if the animal prefers it. Ginger root raw is a little strong, and most animals don't like it. Scale down the human dosage for animals, and give a little before the car ride as well as during the trip if needed. You can buy Hofel's High Strength Ginger 'Pearles' (a fancy name for capsules!) for the dogs and their car sickness. Each capsule contains the same as 12grams of fresh ginger and you only need one per day, given about half an hour before traveling. They have found that it really does help in reducing salivation and nausea.
2. In Pat Colby's book - Natural Pet Care, under the heading Travel Sickness is says "In all species, (including humans) this is due to a vitamin B6 deficiency". Goes on to say "give half a teaspoon of ascorbate, one B complex and one B6, or half of each for a small dog (the two must always be given together). If it is to be a long journey, giving all the recommended vitamins on the feed the day before as well, and during the journey, would also be a good idea as it would guard against the extra stress"
3. Fenugreek, another herb, can be used just like ginger.
4. Rescue Remedy can be given just a few drops on a small treat. This is a Bach Flower Remedy. It tends to calm down an animal but doesn't make them dopey like drugs do. Give about 4 drops in the mouth or ears about 10-12 hours before starting the trip, repeating every four hours or as needed. You can also spritz the car with a dilution made with spring water. RR is absorbed anywhere through the skin, so even rubbing some RR in can help calm. RR can also be given in drinking water - dilution does not affect its efficacy.
5. Peppermint is wonderful for motion sickness. A drop or two of tincture of peppermint might help or try brewing some peppermint tea and giving the animal some cooled tea. This also calms the stomach.
6. Try giving a little raw honey before the car trip. It tends to calm the tummy. Repeat as necessary. (If your animal has a heart problem, however, do not give honey, as it tends to make animals retain fluid, which is not good in the case of heart patients)
7. Behavior. Start the dog (or cat) out by sitting in the car. After several times and the attitude is calm, try starting the car with the dog in it. Wait until the animal is comfortable with a running parked car before driving a short (and I mean SHORT, like down the driveway) distance. *Slowly* keep increasing the time spent in the moving car until the animal is more comfortable with being in a moving car. Spread the "training" out over several weeks for best results. Dosing with any of the 4 remedies above can help too. When in the car, keep your voice cheerful rather than soothing. This will help the animal see that there is nothing scary about being in the car.
8. Try the training on both a full and an empty stomach. Some animals need to eat before riding, some need an empty stomach.
9. When driving to a destination for the first time, make sure it is a fun place. Nothing will undo all your hardwork more quickly than the first visit being a vet clinic or some other "unfun" place. Go to the park or the beach or some other place your dog can look forward to.
10. Some doctors say that carsickness is from a lack of Vit B6, so try giving your dog extra B vits on the morning of the journey. Raw liver (fed the night before or that morning) has lots of B vits, and a human supplement can also be given in pill form. Please give a B complex vitamin rather than just one B vitamin, as they need to be balanced out for maximum effect.
11. Ask your homeopathic vet about perhaps trying one of the following homeopathic remedies (in about the 6th potency): Petroleum, Cocculus, Tabacum, Borax.
Always remember to secure your animal properly in the car. Loose in the back of a truck may look "cool", but your animal can be injured and perhaps killed this way. Crates tied or bolted down in the back of a truck or the back of a car is the safest route. Seatbelts for animals are also available. A simple downstay in the backseat may not be sufficient in preventing injury should an accident occur.
Compiled by and contributed by a SFBAGSRescue volunteer.