Famotidine (sold as Pepcid AC) is the most widely recommended human medicine you can give a vomiting dog at home. It reduces stomach acid and is considered safe for short-term use in dogs at the right dose. But before you reach into your medicine cabinet, it helps to know which options are genuinely safe, which carry hidden risks, and when vomiting signals something a pill won’t fix.
Famotidine (Pepcid AC)
Famotidine is the go-to recommendation from most veterinarians when dog owners need an over-the-counter option. It works by blocking histamine receptors on the cells that produce stomach acid, which lowers acid output and can ease nausea caused by an irritated stomach lining. VCA Animal Hospitals notes that vets often recommend it for occasional dietary indiscretions, the veterinary term for “your dog ate something it shouldn’t have.”
The standard veterinary dose listed in the Merck Veterinary Manual is 0.5 to 1 mg per kilogram of body weight, given once daily by mouth. For a 20-pound dog (about 9 kg), that works out to roughly 5 to 9 mg. Pepcid AC tablets come in 10 mg and 20 mg sizes, so you may need to split a tablet. Use the plain version only. Avoid “complete” or “dual action” formulas, which contain additional active ingredients not tested for dogs.
A few important caveats: famotidine can interfere with the absorption of certain other medications, including some antibiotics and antifungal drugs. If your dog is already on medication, call your vet before adding famotidine. And if the vomiting doesn’t resolve within a day or two, the acid reducer is masking a problem, not solving it.
Bismuth Subsalicylate (Pepto-Bismol)
Pepto-Bismol is sometimes used in dogs, but it comes with more risk than most owners realize. The active ingredient, bismuth subsalicylate, contains a compound closely related to aspirin. In dogs, doses above 0.7 mL per kilogram of body weight can cause salicylate toxicity, which affects the liver, kidneys, and blood clotting. The safe range is narrow: about 0.25 mL per kilogram, given every 4 to 6 hours.
Even at safe doses, expect some harmless but alarming side effects. Your dog’s tongue and stool will turn dark or black, which can also make it harder to spot blood in the stool if something more serious is going on. Pepto-Bismol should never be given to dogs that take blood thinners, diabetes medications, or any anti-inflammatory drug. It’s also unsafe for pregnant dogs, as chronic salicylate exposure can cause fetal abnormalities.
Because the margin between a helpful dose and a harmful one is small, many vets prefer famotidine as the safer first choice. If you do use Pepto-Bismol, stick to the original liquid formula (not chewable tablets with xylitol, which is toxic to dogs) and keep use to a single day at most.
What About Omeprazole (Prilosec)?
Omeprazole is a stronger acid-suppressing drug that works differently from famotidine. Instead of just blocking one signal that triggers acid production, it shuts down the acid-producing pump in stomach cells entirely. Veterinarians do prescribe it for dogs with chronic acid-related conditions like esophagitis or stomach ulcers, but it’s not a great choice for a quick fix at home.
Omeprazole takes longer to reach full effect, and it can reduce the absorption of other oral medications your dog may be taking. For a single episode of vomiting, it’s more firepower than you need. Save this one for situations where your vet specifically recommends it.
Keeping Your Dog Hydrated
Dehydration is the most immediate danger when a dog is vomiting repeatedly. If your dog can keep liquids down, you can offer unflavored Pedialyte diluted 50/50 with water. Undiluted Pedialyte can actually cause diarrhea because of the concentrated electrolytes, so the dilution step matters. Offer small amounts frequently rather than a full bowl at once.
To check for dehydration, gently pinch the skin on the back of your dog’s neck and release it. In a well-hydrated dog, the skin snaps back immediately. If it stays tented for a second or two, your dog needs fluids, and if vomiting prevents drinking, that’s a situation for your vet.
The Bland Diet After Vomiting Stops
Once your dog has gone 12 to 24 hours without vomiting, reintroduce food gradually with a bland diet. The standard recipe is boiled, skinless chicken breast mixed with plain cooked white rice. No butter, no seasoning, no oil. Divide the day’s food into four or more small meals rather than the usual one or two. This gives the stomach less work to do at once.
Stay on the bland diet for two to three days, then slowly mix in your dog’s regular food over the next few days, increasing the ratio of normal food at each meal. Jumping straight back to regular kibble often triggers another round of stomach upset.
When Vomiting Needs a Vet, Not a Pill
A single episode of vomiting in an otherwise energetic, alert dog is usually nothing serious. But certain patterns are red flags that no over-the-counter medication will address:
- Vomiting multiple times in one day or continuing past 24 hours
- Blood in the vomit, which can look red or like dark coffee grounds
- Lethargy or sudden weakness, a drop in energy that signals something internal
- Refusing both food and water for more than 24 hours
- A swollen or painful belly, which can indicate bloat (gastric dilatation-volvulus), a life-threatening emergency especially in large, deep-chested breeds
- Vomiting after swallowing a foreign object like a toy, sock, or bone fragment
- Neurological signs like staggering, tremors, or seizures, which suggest toxin exposure
- Puppies or senior dogs vomiting suddenly, as both groups deteriorate faster
If your dog vomits repeatedly even after drinking water, or if you suspect it ate something toxic, skip the home remedies entirely. These situations can escalate within hours, and stomach acid reducers won’t help with obstructions, toxins, or organ problems. A vomiting dog that still has bright eyes, a wagging tail, and interest in food is a good candidate for a dose of famotidine and a bland diet. A vomiting dog that’s listless, bloated, or in pain needs professional care right away.