What Is Gravol and How Does It Help Dogs?
Gravol is a well-known brand of dimenhydrinate, an antihistamine used to prevent and treat motion sickness and nausea. In some countries the same drug is sold as Dramamine. Dimenhydrinate is used off-label in dogs, most often to help with car and travel sickness.
Dimenhydrinate is closely related to the antihistamine diphenhydramine (the active ingredient in Benadryl). It works on the parts of the brain and inner ear involved in balance and the vomiting reflex, calming the signals that cause nausea, drooling and vomiting during travel. Because it is an antihistamine, it also tends to cause drowsiness, which can have a mild additional calming effect for an unsettled travelling dog.
Veterinarians may suggest Gravol (dimenhydrinate) for dogs that:
- Get carsick or struggle with travel
- Have mild nausea from non-serious causes
It is worth knowing from the outset that, for preventing travel sickness, there are now prescription anti-sickness medications — particularly maropitant (Cerenia) — that are often more effective and far less sedating than dimenhydrinate. Gravol is a familiar, accessible option, but it is not necessarily the best one, and the choice is worth discussing with your vet.
Use the calculator above to understand the typical dose, but a veterinarian should confirm it is appropriate. For more, see PuppaDogs’ guide to Dramamine (dimenhydrinate) for dogs and the Cerenia dosage calculator.
How the Gravol Dosage Calculator Works
The calculator estimates a dimenhydrinate dose from your dog’s body weight. It then:
- Shows the 4–8 mg/kg dose range and a conservative starting dose.
- Converts it into a number of 25 mg or 50 mg tablets.
- Confirms the 8-hourly schedule and the travel timing.
- Flags antihistamine-related cautions.
Enter your dog’s weight, choose the reason for use and the tablet strength, tick any health considerations, then press Calculate Dose.
How Gravol Doses Are Calculated for Dogs
The Dose Range
The commonly used off-label dimenhydrinate dose for dogs is approximately:
4–8 mg/kg of body weight, every 8 hours.
Veterinarians generally suggest starting at the lower end and seeing how the dog responds — both for effectiveness and to gauge the degree of drowsiness.
Timing for Travel
For motion sickness, timing matters: give the dose about 30–60 minutes before the journey begins, so it has taken effect before the car starts moving. Giving it after a dog is already feeling sick is much less effective.
Gravol Dosage Chart for Dogs
This chart shows the per-dose range (4–8 mg/kg). It is a reference only — your veterinarian’s recommendation takes priority.
| Dog weight | Per-dose range (4–8 mg/kg) | Frequency |
|---|---|---|
| 5 kg (11 lb) | 20–40 mg | every 8 h |
| 10 kg (22 lb) | 40–80 mg | every 8 h |
| 20 kg (44 lb) | 80–160 mg | every 8 h |
| 30 kg (66 lb) | 120–240 mg | every 8 h |
| 40 kg (88 lb) | 160–320 mg | every 8 h |
The Critical Safety Rule: Use Only Plain Dimenhydrinate
This is the most important product-safety point. The “Gravol” and “Dramamine” brand names cover a range of different products — and some of them contain more than just dimenhydrinate. There are “multi-symptom,” “extra-strength,” “long-acting,” ginger-based and combination versions, and some contain added ingredients such as decongestants that can be harmful to dogs.
Before giving anything, read the full ingredient list and use only a plain dimenhydrinate product. If the package lists any active ingredient other than dimenhydrinate, do not use it.
How to Give Gravol to Your Dog
- For travel sickness, give it 30–60 minutes before setting off.
- Every 8 hours if repeat doses are needed.
- With or without food — giving it with a little food can help if there is mild stomach upset.
- Hide the tablet in a small treat or pill pocket.
- Watch the first dose for the degree of drowsiness before a long journey.
Side Effects and Safety Warnings
Dimenhydrinate is generally well tolerated, and the most common effect is drowsiness or sedation, because it is an antihistamine. Other possible effects include a dry mouth, and occasionally a paradoxical reaction — restlessness or excitement instead of sedation.
When to Use Caution
Use dimenhydrinate carefully, and only with veterinary advice, in dogs that:
- Have glaucoma — antihistamines can raise eye pressure
- Have urinary retention or an enlarged prostate
- Have heart disease or high blood pressure
- Have a seizure history
- Are taking other sedating medication — the effects add together
- Are pregnant or nursing
A Better Option for Many Dogs
It is worth repeating: while Gravol can help, modern prescription anti-sickness medication is often the better choice for canine travel sickness. Maropitant (Cerenia) in particular is specifically licensed to prevent travel-induced vomiting in dogs, is generally more effective, and does not cause the drowsiness that dimenhydrinate does — so the dog arrives alert rather than sedated. If your dog regularly suffers from car sickness, ask your veterinarian about Cerenia and other options rather than relying on Gravol alone.
Conclusion
Gravol (dimenhydrinate) is a familiar, accessible antihistamine that can help some dogs with motion sickness and mild nausea, dosed at roughly 4–8 mg/kg every 8 hours, given 30–60 minutes before travel. The calculator above gives a sensible estimate and converts it into tablets. Two things matter most: use only a plain dimenhydrinate product — never a multi-symptom or decongestant-containing version — and remember that a modern prescription anti-sickness drug such as Cerenia is often more effective and less sedating. Confirm the plan with your veterinarian, who can help you choose the best approach for your dog’s travel sickness.
Frequently Asked Questions
How much Gravol can I give my dog?
The commonly used off-label dimenhydrinate (Gravol) dose for dogs is about 4-8 mg/kg of body weight, every 8 hours, usually started at the lower end. As a guide that is roughly 40-80 mg for a 10 kg dog. For travel sickness it should be given 30-60 minutes before the journey. Confirm the dose with your veterinarian.
Is Gravol safe for dogs?
Plain dimenhydrinate (Gravol) is considered relatively safe for many dogs when dosed correctly under veterinary guidance, with drowsiness being the main effect. However, you must use only a plain dimenhydrinate product – never a multi-symptom or combination version – and use caution in dogs with glaucoma, urinary retention, heart disease or a seizure history.
When should I give my dog Gravol for car sickness?
For motion or travel sickness, give Gravol about 30-60 minutes before the journey begins, so it has time to take effect before the car starts moving. Giving it after a dog already feels sick is much less effective. It can be repeated every 8 hours if needed.
Can I give my dog any Gravol product?
No – use only a plain dimenhydrinate product. The Gravol and Dramamine brands cover several different formulations, and some multi-symptom, extra-strength or combination versions contain added ingredients such as decongestants that can be harmful to dogs. Always read the full ingredient list before giving any human medication to a dog.
What are the side effects of Gravol in dogs?
Dimenhydrinate is an antihistamine, so the most common side effect is drowsiness or sedation. Other possible effects include a dry mouth and, occasionally, a paradoxical reaction with restlessness instead of calm. Watch how your individual dog responds, especially before a long journey.
Is Cerenia better than Gravol for dog travel sickness?
For preventing travel sickness, the prescription drug maropitant (Cerenia) is often a better choice than Gravol. Cerenia is specifically licensed to prevent travel-induced vomiting in dogs, is generally more effective, and does not cause the drowsiness that dimenhydrinate does. Ask your veterinarian which option suits your dog best.
Related PuppaDogs Calculators
Continue building your dog’s personalised care plan with these related PuppaDogs calculators:
- Dog Pregnancy / Whelping Due-Date Calculator
- Puppy Weight Predictor (Adult Weight Calculator)
- Heatstroke Risk Calculator for Dogs
- Bloat (GDV) Risk Calculator for Dogs
- Dog Life Expectancy Calculator (Breed, Body Condition, Lifestyle)
- Spay/Neuter Timing Calculator for Dogs (Breed-Specific)
References & Further Reading
The dosing ranges and safety information on this page are drawn from the following veterinary references. Always defer to your own veterinarian and the manufacturer’s label for your specific product.
- Plumb DC. Plumb’s Veterinary Drug Handbook. 10th ed. Hoboken, NJ: Wiley-Blackwell, 2023 – dimenhydrinate monograph.
- Merck Veterinary Manual. Antihistamines; motion sickness and antiemetic therapy in dogs. merckvetmanual.com.
- Veterinary Partner (VIN). Dimenhydrinate (Dramamine, Gravol) for dogs and cats. veterinarypartner.vin.com.
- American Animal Hospital Association (AAHA). Management of motion sickness and nausea in dogs. aaha.org.
- PuppaDogs. Dramamine Dosage for Dogs: Safe Canine Travel Tips. puppadogs.com.
