When your old dog is shaking and not eating but drinking water, it’s natural to feel worried and uncertain.
These symptoms—trembling, refusal to eat, and continued water consumption—often point to a variety of potential health concerns, especially in senior dogs.
We outline the common causes of your old dog shaking and not eating but drinking water. We’ll also outline what to do next and when veterinary intervention is needed.
Old Dog Shaking and Not Eating But Drinking Water: Why It Happens
An old dog shaking and not eating but drinking water is a combination of symptoms in senior dogs is often a sign of underlying health issues that range from mild to serious.
Common causes include pain or discomfort due to aging, gastrointestinal issues, kidney disease, liver problems, neurological disorders, nausea or toxin ingestion, hypoglycemia, infections or fever, emotional stress or anxiety, side effects from medication, and cancer.
Old Dog Shaking and Not Eating But Drinking Water: Common Causes
Pain or discomfort due to aging
One of the most common reasons an old dog is shaking and not eating but drinking water is age-related pain or discomfort.
Conditions like arthritis, hip dysplasia, or degenerative joint disease become more prevalent as dogs get older.
These issues can cause significant pain, which may result in trembling limbs, loss of appetite, and lethargy.
When in pain, your dog might avoid food because chewing or moving to the food bowl causes discomfort.
However, drinking water is less physically taxing, which is why your dog may still drink.
Pain in senior dogs may also stem from dental disease, which can make eating painful while leaving the urge to drink water unaffected.
Related: Dog shaking and not eating (Causes and what to do)
Gastrointestinal issues
Digestive problems are another frequent culprit when an old dog is shaking and not eating but drinking water.
An upset stomach, gas, or bloating can lead to trembling and nausea, which suppresses appetite.
Older dogs may also suffer from pancreatitis or inflammatory bowel disease (IBD), both of which cause abdominal pain and appetite loss.
Even if your dog isn’t eating, they might still drink water to soothe stomach discomfort or because dehydration begins to set in.
Kidney disease
Chronic kidney disease is common in older dogs and often presents as a loss of appetite, shaking, and increased thirst.
If your old dog is shaking and not eating but drinking water, it could be because their kidneys are not filtering toxins effectively, leading to nausea and weakness.
Shaking may result from an electrolyte imbalance caused by kidney malfunction.
In many cases, excessive water consumption is an early symptom, followed by vomiting, weight loss, and muscle tremors.
Liver problems
An old dog shaking and not eating but drinking water could also be experiencing liver disease.
The liver processes toxins, and when it starts to fail, these toxins can build up in the bloodstream.
This leads to neurological symptoms, such as shaking or seizures, and reduces appetite.
However, water consumption might remain the same or even increase in response to nausea or dehydration.
Liver issues in senior dogs can develop due to long-term medication use, infections, or congenital defects that worsen with age.
Neurological disorders
Senior dogs are at risk for neurological conditions like canine cognitive dysfunction (CCD), seizures, and vestibular disease.
These issues can result in trembling, disorientation, or even a reluctance to eat due to confusion or dizziness.
A dog with CCD may forget where their food bowl is or lose interest in eating altogether.
Meanwhile, vestibular disease can cause loss of balance, shaking, and nausea—again leading to food refusal, but not necessarily a halt in water intake.
Related: Old dog shaking and not eating (Here’s why)
Nausea or toxin ingestion
If your old dog is shaking and not eating but drinking water, consider the possibility of toxin exposure.
Dogs can ingest harmful substances like spoiled food, human medication, or household cleaners.
This can cause nausea, vomiting, and trembling.
They may drink water in response to thirst or try to flush the toxin from their system.
Nausea can also occur due to other causes like motion sickness, stress, or side effects of medications, all of which may cause your dog to stop eating.
Hypoglycemia
Low blood sugar (hypoglycemia) is less common in older dogs than in puppies but can still occur, especially in dogs with diabetes or insulin imbalances.
When blood sugar drops, dogs may shake or tremble and feel too weak or disoriented to eat.
They may still drink water to relieve dry mouth or discomfort.
Prolonged hypoglycemia is dangerous and requires swift attention.
Infections or fever
Infections—bacterial, viral, or fungal—can lead to symptoms like shaking, lethargy, and anorexia.
If your old dog is shaking and not eating but drinking water, they could be battling a systemic infection or fever.
As their body fights the infection, their appetite often decreases.
Drinking may continue due to increased body temperature and dehydration risk.
Emotional stress or anxiety
Old dogs are not immune to emotional distress. Changes in their environment, such as moving to a new home, the absence of a family member, or loud noises, can cause anxiety.
Shaking is a common physical response to stress, and stress may also reduce appetite.
However, these dogs often continue drinking water, especially if stress increases panting or leads to a dry mouth.
Side effects from medication
If your old dog is on medication for arthritis, heart issues, or any other chronic condition, the side effects may include shaking, nausea, and decreased appetite. Some drugs can cause gastrointestinal upset or sedation, which can result in a dog not wanting to eat.
On the other hand, medications like corticosteroids may increase thirst, so you might notice your dog is drinking but not eating.
Cancer
Sadly, cancer is a major concern in senior dogs and can cause a combination of symptoms, including shaking, loss of appetite, weakness, and weight loss.
Tumors can lead to internal pain, gastrointestinal blockages, or metabolic changes that suppress hunger.
Dogs with cancer may continue to drink water, particularly if they have a fever or if the cancer affects organs like the kidneys or liver.
What to do if your old dog is shaking and not eating but drinking water
If your old dog is shaking and not eating but drinking water, it’s important not to wait too long before seeking veterinary attention.
While mild cases may be due to temporary discomfort or anxiety, persistent or worsening symptoms can quickly turn serious in older dogs.
Here’s what you should do:
1. Monitor symptoms closely
Keep an eye on your dog’s behavior.
Note any additional symptoms like vomiting, diarrhea, limping, bloated abdomen, or labored breathing.
Record how much water they’re drinking and whether they’re urinating more or less than usual.
2. Try offering bland food
Offer bland food such as boiled chicken and rice to see if your dog will eat.
If they refuse even their favorite treats or soft food, this confirms appetite loss.
3. Check for signs of pain
Gently feel around your dog’s body to check for areas of sensitivity, swelling, or stiffness.
Watch for limping, difficulty getting up, or whining when touched.
4. Avoid giving human medications
Do not give your dog any over-the-counter human medications without consulting a vet.
These can be toxic to dogs, especially older ones with weakened organs.
5. Schedule a vet appointment
If your dog shows no signs of improvement after 24 hours, or if symptoms worsen, schedule a visit to the vet immediately.
Bloodwork, X-rays, or ultrasounds may be needed to determine the underlying cause.
6. Stay calm and supportive
Older dogs can pick up on your stress.
Keep them warm, comfortable, and in a quiet environment while you wait for professional care.
Key Takeaway
An old dog shaking and not eating but drinking water should never be ignored.
These symptoms, especially when seen together, often point to an underlying health issue.
From age-related pain and organ disease to nausea, stress, or even cancer, the causes are many—and potentially serious.
Timely veterinary evaluation is the best way to get to the root of the problem.
With early diagnosis and proper treatment, many of the conditions causing these symptoms can be managed, helping your senior dog enjoy a better quality of life in their golden years.