Health
What should I do during a seizure?
Time it, film it, clear the space around the dog, keep the room quiet and dim, and keep your hands well away from the mouth.
← Back to breed profile
Epilepsy in Mastiff (English Mastiff)s
Quick answer
What should I do during a seizure?
Time it, film it, clear the space around the dog, keep the room quiet and dim, and keep your hands well away from the mouth.
Watching is, in fact, almost exactly what you should be doing. The two most useful things during a seizure are a stopwatch and a camera.
Owners who have just witnessed a first seizure and are trying to work out whether to drive to an emergency clinic tonight, and owners of diagnosed dogs managing long-term medication and trying to judge whether control is good enough.
Important reminder
This guide is not medical advice. If your dog shows pain, sudden behavior change, or worsening symptoms, consult a licensed veterinarian.
Some links may be affiliate links. We may earn a commission at no extra cost to you. We only suggest products we believe are helpful for dog owners.
We research and check what we publish, but we do not warrant that any figure, date, price, or statement is accurate, complete, or current, and we accept no liability for any loss, cost, injury, or other harm arising from the use of this site. Use it as one reference among several. You remain responsible for your own decisions and for your dog's care - confirm anything that matters with a licensed veterinarian or another qualified professional before you act on it. Full disclaimer.
Check this first
Which seizures need an emergency clinic tonight
Not every seizure is an immediate emergency, and knowing the difference prevents both dangerous delay and unnecessary panic.
Go immediately, without waiting, if a seizure lasts more than about five minutes, if the dog has two or more seizures without fully recovering consciousness between them, or if it has three or more separate seizures within twenty-four hours. Prolonged and clustered seizures are genuinely dangerous, because muscle activity generates heat and a very large dog overheats quickly, and because prolonged seizure activity damages the brain. This is one of the true emergencies in neurology.
Also go straight in if the dog does not return to normal within an hour or so, if it seems blind or cannot stand, if there is any possibility it ate something toxic, or if it has sustained an injury during the event.
A single short seizure in a dog that recovers and is behaving normally an hour later is a call to your vet the next morning, not a midnight drive, though many owners will go anyway and no vet will criticise them for it.
The recovery period afterwards deserves warning. For anything from minutes to a full day the dog may be disorientated, pace, bump into things, appear blind, be ravenously hungry or be uncharacteristically clingy or irritable. This post-ictal phase frightens owners more than the seizure sometimes, and with a two-hundred-pound dog stumbling around a kitchen it also carries genuine injury risk. Give the dog a safe, confined, non-slip space and leave it alone as far as possible.
On diagnosis: a first seizure in a middle-aged or older large dog is investigated differently from one in a young adult. Idiopathic epilepsy, meaning epilepsy with no identifiable cause, typically begins between one and five years. A first seizure in a dog over about six raises more concern about an underlying cause, including a brain tumour, which is a relevant consideration in a breed with a documented cancer burden.
If any of these apply, call your vet or an emergency clinic now. The rest of this page is for the cases that are not an emergency.
What this problem looks like
A seizure is a burst of abnormal electrical activity in the brain, producing loss of consciousness, collapse, stiffening and paddling, often with salivation and loss of bladder control. Epilepsy is the term for recurrent seizures. Some cases have an identifiable cause in the brain or elsewhere in the body, while idiopathic epilepsy means recurrent seizures with no cause found despite proper investigation.
Common triggers
- Idiopathic epilepsy, where no underlying cause is identified despite investigation
- Structural brain disease including tumours, particularly relevant in older large dogs
- Metabolic problems such as liver disease or low blood sugar
- Toxins, including some household and garden products
- Missed doses of anti-seizure medication in a dog already being treated
Epilepsy affects a small percentage of dogs overall and is not among the documented health issues of the English Mastiff. It is included here because a seizure in a very large dog is a distinctive practical problem, and because the way a first seizure is investigated depends heavily on the dog's age, which matters in a breed with a lifespan of only nine to eleven years and a documented cancer burden.
Why this happens
Breed factors
There is no established Mastiff predisposition to epilepsy and it would be wrong to suggest one. What the breed changes is the practical management. A two-hundred-pound dog seizuring in a confined space is a genuine hazard to itself and to furniture, generates a great deal of heat during prolonged muscle activity, and cannot be lifted or carried by one person afterwards. The breed's short lifespan also means a higher proportion of first seizures occur in the age bracket where an underlying cause is more likely.
Environment factors
The environment does not cause epilepsy but it determines how much injury a seizure produces. Hard flooring, stairs, sharp furniture corners, garden ponds and enclosed spaces are all hazards for a dog that may fall without warning. Overheating during a prolonged event is a real risk in a heavy dog, and worse in warm weather. Access to toxins matters too, since a Mastiff can reach worktops, bins and garden chemical stores that a smaller dog cannot.
What you can do at home (once it is not an emergency)
When to talk to your vet
Contact your vet after any first seizure, and go immediately as an emergency if a seizure lasts more than about five minutes, if there are two or more without full recovery between them, if there are three or more within twenty-four hours, if the dog does not return to normal within roughly an hour, if it seems blind or cannot stand, if it may have eaten something toxic, or if it was injured during the event. Prolonged seizure activity causes brain damage and dangerous overheating, particularly in a heavy dog, and is treatable only in a clinic. Never give any human medication.
At home, alongside your vet's plan
- Keep a written seizure diary with date, clock time, duration and circumstances. It is the single most useful thing you will bring to any appointment.
- Film events where you safely can. Owners routinely misremember duration and appearance, and video removes the guesswork.
- Seizure-proof one ground-floor room: non-slip flooring, no stairs, nothing hard or sharp within falling distance, and a gate.
- Set alarms for medication and never miss a dose, since abrupt gaps in anti-seizure treatment can precipitate clusters.
- Fit a camera if the dog is ever alone, so events that happen in your absence are recorded rather than inferred from the aftermath.
More Mastiff health & behavior issues
- Liver Shunts in Mastiffs: The Puppy That Does Not Thrive
- Mastiff Cardiomyopathy: Reading the Echo Report and What Follows
- Mastiff Kidney and Bladder Stones: Signs and the Emergency
- Mastiff Kidney Disease: Catching It Before Two Thirds Is Gone
- Mastiff Pancreatitis: The Counter-Surfing Emergency
- Pancreatitis and Diabetes in Senior Mastiffs: The Connection
- Facial Fold Skin Infections in Mastiffs: A Loose-Skin Problem
- Luxating Patellas in Mastiffs: Usually the Wrong Diagnosis
- Mastiff Allergies: Itching, Ear Infections & Skin Folds
- Mastiff Obesity: Why Twenty Extra Pounds Is Invisible and Serious
- Patellar Luxation Grades in a Mastiff: Reading the Diagnosis
- Separation Anxiety in Mastiffs: When a Gentle Giant Falls Apart Alone
- Skin Allergies in Mastiffs: What Owners Actually Pay
- Exercise-Induced Collapse in Mastiffs: What's Actually Going On
- Legg-calvé-perthes Disease in Mastiffs: Signs, Costs and What to Do
Epilepsy in other breeds
- Jack Russell Terrier Epilepsy: Triggers, Signs & Treatment
- Labradoodle Epilepsy: Triggers, Signs & Treatment
- Maltese Epilepsy: Triggers, Signs & Treatment
- Miniature Schnauzer Epilepsy: Triggers, Signs & Treatment
- Poodle Epilepsy: Triggers, Signs & Treatment
- Rottweiler Epilepsy: Triggers, Signs & Treatment
- Standard Schnauzer Epilepsy: Triggers, Signs & Treatment
- Yorkshire Terrier Epilepsy: Triggers, Signs & Treatment
- Akita Epilepsy: Recognizing Seizures & Long-Term Management
- Australian Shepherd Epilepsy: Seizure Signs & Emergency Care
See all Mastiff health problems, which breeds are prone to epilepsy, or the full Mastiff breed guide for temperament, exercise needs and ownership costs.
What to expect, and how you know it is working
Investigation of a first seizure typically involves bloodwork immediately and, depending on age and findings, advanced imaging within a few weeks. Once medication starts, expect two to three months of dose adjustment and blood level monitoring before control settles. Treatment is then usually lifelong, with monitoring every six to twelve months and dose reviews after any cluster.
Success is usually defined as fewer and shorter seizures with acceptable side effects, not the complete absence of them. A commonly used benchmark is a substantial reduction in frequency with no clusters and no emergency admissions. Alongside that, success means a household that knows exactly what to do, has a safe room prepared, and no longer experiences each event as a crisis.
What to do while it is happening
Almost every instinct in this situation is wrong. Here is what actually helps.
- Start timing. Note the clock time it began and how long it lasts. This single number changes what your vet does next more than anything else you can provide.
- Do not put your hands near the mouth. The dog cannot swallow its tongue, and a Mastiff's jaws in a seizure will cause a serious injury without any intention behind it.
- Clear the space instead of moving the dog. Slide furniture away, block a staircase, and put a cushion between the head and any hard surface if you can do so safely.
- Dim the lights, turn off the television and keep the room quiet, since sensory input can prolong the event.
- Film it if you can. Thirty seconds of video is more informative to a neurologist than any description, and owners consistently misremember what happened.
What to do next about epilepsy in Mastiffs
If you think your Mastiff has epilepsy, the plan is three steps: write down what you have seen and when it started, book a veterinary appointment rather than waiting for the next flare, and take video of the behaviour or symptom before you go — the thing you are worried about rarely happens in the consulting room. Screening in the parents covers hip dysplasia, elbow dysplasia, cancer.
What the vet visit should produce is a diagnosis and a written plan, not just reassurance: what is being ruled out, what the monitoring interval is, and which signs mean you come back sooner. Ask what the treatment costs across a year rather than per visit, because that is the number that decides whether you are managing this condition or reacting to it.
Between appointments, keep a short log — dates, what you saw, what changed. It is the single most useful thing an owner brings to a follow-up, and for epilepsy it is often what separates a clear pattern from a guess.
The three minutes that felt like twenty
Rhoda's Mastiff Kip had his first seizure on a Sunday evening. She described it afterwards as lasting at least fifteen minutes, and she drove to the emergency clinic convinced he was dying. The second one, six weeks later, was recorded. Her partner had put a camera in the kitchen after the first event. It lasted two minutes and forty seconds. That number mattered. It moved Kip out of the category of prolonged seizure requiring emergency intervention and into the category of a dog to be worked up calmly. Bloodwork was unremarkable, an MRI at seven years old found no structural cause, and Kip was started on medication with a target of reduction rather than elimination. He now averages one short seizure every four or five months. Rhoda keeps the diary in a notebook by the kettle and says the camera changed everything, not because it treated anything but because it replaced her worst estimate with a fact.
Key takeaway: Owners consistently overestimate how long a seizure lasted, and duration is the number that determines urgency. Time it, or better, film it.
Frequently asked questions
Should I take my dog to the vet after a single seizure?
Yes, but the urgency depends. A single short seizure in a dog that has fully recovered warrants a call the next morning. A seizure lasting over five minutes, repeated seizures without recovery in between, or three or more within a day is an emergency requiring immediate attention.
Can my dog swallow its tongue?
No. This is a persistent myth and acting on it is how owners get badly bitten. Keep hands away from the mouth entirely. A Mastiff's jaws closing involuntarily on a hand cause serious damage, and there is nothing useful you could achieve there anyway.
Are Mastiffs prone to epilepsy?
Epilepsy is not among the documented health issues for the English Mastiff, which centre on joints, heart, eyes, cancer, bloat and thyroid. It is recognised in many breeds. In a Mastiff, a first seizure in a dog over six should prompt particular attention to underlying causes given the breed's documented cancer risk.
What triggers seizures?
In idiopathic epilepsy there is often no identifiable trigger. Some owners identify patterns around sleep, excitement, stress or missed medication. Keeping a written seizure diary with dates, times and circumstances is the only reliable way to find a pattern, and it is also what guides medication decisions.
Will medication stop the seizures completely?
Usually it reduces their frequency and severity rather than eliminating them. A common goal is fewer, shorter, less severe seizures with an acceptable quality of life, not zero. Expect the dose to be adjusted over months, and expect regular blood monitoring, which is part of the treatment rather than an optional extra.
Is anti-seizure medication expensive for a giant breed?
Yes, meaningfully. These drugs are dosed by body weight and a Mastiff may weigh five times what a mid-sized dog does. Add regular blood monitoring for drug levels and organ function, and it becomes a substantial ongoing cost. Ask your vet for an annual figure at the outset.
Can I ever leave my epileptic dog alone?
Most owners do, with sensible precautions: a confined ground-floor space, non-slip flooring, no stairs and nothing hard to fall against. A camera helps enormously, both for peace of mind and because it captures events you would otherwise only find evidence of afterwards.
Quick answers
View more answersHealth
When is a seizure an emergency?
Over five minutes, two or more without full recovery in between, or three or more in twenty-four hours. Go immediately.
Behavior
Why is my dog strange for hours afterwards?
That is the post-ictal phase. Disorientation, pacing, apparent blindness and ravenous hunger are normal and can last up to a day.
Health
Does a first seizure at eight mean something different?
Yes. Idiopathic epilepsy usually starts between one and five. A first seizure in an older dog raises more concern about an underlying cause.
Living
What records should I keep?
A diary of every event: date, clock time, duration, what preceded it, and how long recovery took. It guides every medication decision.
Related DogBreedCompass guides
- cancer in Mastiffs – Brain tumours are a specific concern behind late-onset seizures in this breed.
- cardiac disease in Mastiffs – Collapse from cardiac causes can be mistaken for a seizure.
- chronic hepatitis in Mastiffs – Liver disease is one of the metabolic causes screened for after a first seizure.
- anaesthesia in a Mastiff – Long-term medication requires monitoring bloods and careful anaesthetic planning.
- Mastiff cost breakdown – Weight-based medication and monitoring is a substantial recurring cost.
Bring the right questions to the vet
A one-page prep sheet for this condition: the signs, the questions to ask, what to get priced. Unlocks here.
You get: Vet visit prep sheet
No spam. One-click unsubscribe. See our privacy policy.
Preview page 1 before you decide.
Related guides
Comparison
Mastiff (English Mastiff) vs Shiba Inu: Size, Cost & Temperament
ComparisonRead guide->
Comparison
Basset Hound vs Mastiff (English Mastiff): Full Breed Comparison
ComparisonRead guide->
Comparison
Australian Shepherd vs Mastiff (English Mastiff): Full Comparison
ComparisonRead guide->
Cost
Mastiff (English Mastiff) Cost in Wilmington, DE: A Real Budget
CostRead guide->
Comparison
Chinese Shar-Pei vs Mastiff (English Mastiff): Full Comparison
ComparisonRead guide->
Comparison
Mastiff (English Mastiff) vs Weimaraner: Size, Cost & Temperament
ComparisonRead guide->