Grape and Raisin Poisoning Symptoms in Dogs: Hour-by-Hour Timeline

Q: How long after eating grapes will a dog be sick?

Vomiting typically begins within 6 hours of grape or raisin ingestion, often within 1-2 hours. However, the more serious kidney damage develops over 24-72 hours and may not produce obvious external symptoms until significant damage has occurred. Absence of vomiting does not mean the dog is safe.

Q: What are the signs of grape poisoning in dogs?

Signs include vomiting (often within 6 hours, sometimes containing grape or raisin pieces), diarrhoea, lethargy, decreased appetite, abdominal tenderness (6-24 hours), reduced or no urination (24-48 hours), bad breath with an ammonia or uraemic odour, dehydration, and possible mouth ulcers. Reduced urination after known grape ingestion is a red-flag symptom requiring immediate emergency veterinary attention.

If your dog has eaten grapes or raisins, do not wait for symptoms. Call now:

ASPCA: (888) 426-4435 Pet Poison: (855) 764-7661

Critical: Absence of Symptoms Does Not Mean Safe

Acute kidney injury (AKI) from grape or raisin ingestion develops progressively over 24-72 hours. A dog can appear completely normal for the first 12-24 hours while kidney damage is occurring at the cellular level. Blood tests showing rising creatinine and BUN are often the only way to detect early kidney injury. Do not wait for visible symptoms before seeking veterinary care after any confirmed grape or raisin ingestion.

0 to 6 Hours

CALL POISON CONTROL NOW

Vomiting

The most common first sign. May begin within 1-2 hours of ingestion. Vomit may contain identifiable grape or raisin pieces. Vomiting that contains grape material is direct confirmation of ingestion.

Diarrhoea

May occur alongside vomiting. Can be loose or watery. Usually resolves within the first few hours if kidney injury does not progress.

Lethargy

Some dogs appear normal in the first few hours. Others may seem subdued or less interested in activity immediately after ingestion.

Apparent normality

Do not be reassured by a dog that appears normal in the first 6 hours. The kidney damage that causes the most serious harm develops over the subsequent 24-72 hours without necessarily producing obvious symptoms.

Recommended action at this stage:

The 2-hour window after ingestion is the optimal time for decontamination (vet-guided vomiting induction). Even if vomiting has already occurred, call poison control. Kidney monitoring is still required.

6 to 24 Hours

CALL POISON CONTROL / VET

Persistent lethargy

Dog becomes increasingly subdued, unwilling to play or exercise, may spend more time lying down.

Decreased appetite

Reduced interest in food or treats. A dog that normally eats eagerly refusing food is notable.

Continued vomiting

Some dogs continue to vomit after the initial episode. Persistent vomiting at this stage suggests active toxicity.

Abdominal tenderness

The dog may react to gentle pressure on the abdomen by wincing, pulling away, or growling. This indicates abdominal discomfort, possibly from kidney inflammation.

Reduced water intake

Some dogs drink less during this phase. Note that normal drinking can later decrease as kidney function is compromised.

Recommended action at this stage:

If not already under veterinary care, seek veterinary assessment now. Blood work should be taken to establish baseline creatinine and BUN values. IV fluid therapy is typically initiated at this stage.

24 to 48 Hours

EMERGENCY VET IMMEDIATELY

Reduced urination (oliguria)

Producing less urine than usual is one of the most important warning signs of acute kidney injury (AKI). Monitor urination frequency carefully. A dog that normally urinates every 4-6 hours urinating less frequently than this is abnormal.

Bad breath with ammonia/uraemic odour

When kidneys fail to filter waste products, urea builds up in the blood (uraemia). This produces a characteristic ammonia-like or fishy odour on the breath. If you notice this smell, go to an emergency vet immediately.

Increased thirst initially, then decreased

Dogs in early AKI sometimes drink more as the kidneys try to compensate. As function declines, thirst may decrease alongside urine production.

Dehydration

Dry or tacky gums, skin that does not spring back when gently tented, sunken eyes. Dehydration can be assessed at home but requires veterinary treatment.

Mouth ulcers

Uraemia can cause ulceration of the mucous membranes in the mouth. Check for redness, sores, or reluctance to eat.

Recommended action at this stage:

Any reduction in urination after known grape ingestion is a medical emergency. Go to an emergency vet now. Do not wait for morning. Blood work will show rising creatinine and BUN if AKI is developing.

48 to 72+ Hours

CRITICAL - EMERGENCY VET NOW

Anuria (no urine production)

Complete cessation of urine production indicates established severe AKI. This is a critical medical emergency. The kidneys are no longer filtering waste from the blood. Death can occur within hours without aggressive veterinary intervention.

Severe lethargy and weakness

The dog may be unable to stand or walk. Extreme weakness, unresponsiveness, or collapse.

Tremors or seizures

Uraemic toxins accumulating in the blood can cause neurological symptoms including tremors and seizures in severe cases.

Vomiting blood (haematemesis)

Uraemia can cause gastrointestinal ulceration, leading to bloody vomiting.

Severe dehydration

Despite the kidneys failing to produce urine, the dog may be severely dehydrated. IV fluid therapy is critical.

Recommended action at this stage:

This stage represents established AKI with a serious or guarded prognosis. Immediate hospitalisation with aggressive IV fluid therapy, electrolyte correction, and potentially dialysis (where available) is required. Long-term kidney function may be permanently reduced even in dogs that survive.

What Vets Monitor After Grape Ingestion

Veterinarians use blood and urine tests to detect kidney injury before obvious external symptoms appear. These tests are typically performed at baseline (on admission), and then at 24h and 72h intervals:

Test	What it measures	Significance in AKI
Creatinine (serum)	Waste product filtered by kidneys	Rises as kidney filtration function decreases. Key AKI marker.
BUN (blood urea nitrogen)	Nitrogen waste from protein metabolism	Rises alongside creatinine in kidney injury. Elevated BUN with elevated creatinine confirms AKI.
Phosphorus	Mineral regulated by kidneys	Hyperphosphataemia (high phosphorus) develops as kidneys lose ability to excrete it.
Calcium	Mineral regulated by kidneys	Hypercalcaemia (high calcium) has been documented in some grape toxicity cases.
Urine specific gravity	Concentration of urine	Isosthenuria (urine concentration matching blood concentration) indicates kidneys have lost concentrating ability.
Urine output (ml/kg/hour)	Volume of urine produced	Oliguria (<0.5 ml/kg/hour) is an early AKI sign. Anuria (no urine) indicates severe AKI.
CBC (complete blood count)	Red and white blood cells, platelets	Anaemia may develop in prolonged AKI. Elevated white cells may indicate secondary infection.

Go to an Emergency Vet Immediately If You See:

!Any reduction in urination after known grape ingestion

!Ammonia or uraemic odour on the breath

!Inability to stand or walk

!Tremors or seizures

!Bloody vomiting or diarrhoea

!Complete loss of appetite lasting more than 24h

!Extreme lethargy or unresponsiveness

!Pale or grey gums (sign of poor circulation)

Frequently Asked Questions

How long after eating grapes will a dog be sick?

Vomiting typically begins within 6 hours of grape or raisin ingestion, often within 1-2 hours. However, the serious kidney damage develops over 24-72 hours and may not produce obvious external symptoms until significant damage has occurred. Absence of vomiting does not mean the dog is safe.

What are the signs of grape poisoning in dogs?

Signs include vomiting (often within 6 hours, sometimes containing grape or raisin pieces), diarrhoea, lethargy, decreased appetite, abdominal tenderness (6-24 hours), reduced or no urination (24-48 hours), bad breath with an ammonia or uraemic odour, dehydration, and possible mouth ulcers. Reduced urination after known grape ingestion is a red-flag symptom.

How do I know if my dog has kidney injury from grapes?

External signs of kidney injury (reduced urination, bad breath, lethargy) appear 24-48 hours after ingestion. The only reliable way to detect early kidney injury before these signs appear is blood tests showing elevated creatinine and BUN. This is why veterinary assessment is recommended for all grape ingestions even when the dog appears normal.

My dog ate grapes yesterday and seems fine. Is it safe now?

Not necessarily. Kidney injury can develop up to 72 hours after ingestion. If blood tests were not performed at 24h and 72h post-ingestion, there is no way to confirm kidney function is unaffected. Contact your vet for a blood test if this has not been done. Watch for any reduction in urination, which is an early AKI sign.