If your old dog is shaking and not eating, it can be worrying and emotionally distressing.
These signs often indicate an underlying issue that shouldn’t be ignored. A senior dog’s body is more vulnerable to stress, illness, and organ dysfunction, which makes symptoms like shaking and appetite loss more concerning than in younger dogs.
While occasional appetite changes or shivers can be harmless, persistent signs—especially when combined—may point to more serious problems.
We outline the common causes of an old dog shaking and not eating, what these signs might mean, and what you should do to help.
Here’s why old dog shaking and not eating happens
An old dog shaking and not eating can be caused by a range of underlying issues that become more common with age.
These include pain or discomfort, gastrointestinal issues, hypoglycemia, infections, kidney or liver disease, neurological disorders, anxiety or stress, cold or hypothermia, poisoning, and side effects of medication.
In older dogs, even minor health disturbances can lead to noticeable changes like tremors and appetite loss, making it important to identify and address the root cause promptly to prevent complications.
Old Dog Shaking and Not Eating: Common Causes
Pain or discomfort
One of the most common reasons for an old dog shaking and not eating is pain. Senior dogs are more prone to joint pain from arthritis, spinal issues, or hip dysplasia.
They may shake as a reaction to discomfort and refuse food due to the stress it causes.
Oral pain such as dental disease is also common in older dogs and may lead to reluctance to eat and physical trembling.
Pain from internal conditions like pancreatitis, kidney disease, or cancer can also manifest as shaking and loss of appetite.
Since older dogs often have a decreased pain threshold and less resilience, these symptoms should be closely monitored.
Related: Dog shaking and not eating (Causes and what to do)
Gastrointestinal issues
An upset stomach can be another reason for an old dog shaking and not eating.
Conditions such as gastritis, ulcers, or intestinal blockages can cause nausea, cramping, or abdominal pain—all of which can lead to trembling and refusal to eat.
In senior dogs, digestion can slow down or become more sensitive, making them more prone to such issues.
Shaking due to nausea is particularly common in dogs, and it’s often accompanied by drooling, licking lips, or swallowing repeatedly.
If your senior dog hasn’t eaten in over 24 hours and is trembling, there’s a risk of dehydration and further complications.
Hypoglycemia (Low Blood Sugar)
Older dogs, especially those with underlying conditions like diabetes, liver problems, or pancreatic tumors, are susceptible to hypoglycemia.
A sudden drop in blood sugar levels can result in shaking, lethargy, disorientation, and not eating.
This is more likely in small-breed senior dogs, whose glucose levels can fluctuate rapidly.
If your dog appears weak, confused, or collapses along with the shaking and appetite loss, this is an emergency and should be treated immediately.
Related: Dog shaking and not eating or drinking (Here’s why)
Infections
Infections, whether bacterial, viral, or parasitic, can lead to a combination of symptoms, including an old dog shaking and not eating.
Urinary tract infections, respiratory infections, and even tick-borne diseases like Lyme disease can cause fever, discomfort, and loss of appetite in older dogs.
Sepsis, a serious systemic infection, can also lead to full-body shaking and complete appetite loss.
Older dogs are more vulnerable because their immune systems are typically weaker than those of younger animals.
Kidney or liver disease
Organ dysfunction is unfortunately common in aging dogs.
Kidney and liver disease can both result in toxin buildup in the body, which can trigger symptoms such as shaking, vomiting, nausea, and refusal to eat.
These diseases may develop slowly over time and may not show any signs until they become advanced.
If your old dog is shaking and not eating along with other symptoms like increased thirst, urination, vomiting, or weight loss, organ disease should be considered as a possible cause.
Neurological disorders
Conditions affecting the brain or spinal cord can also result in tremors and appetite changes.
Canine cognitive dysfunction, often described as the dog version of dementia, can cause disorientation, shaking, and changes in eating behavior.
Dogs may forget where their food is, lose interest in eating, or become anxious, which leads to trembling.
Other neurological issues, such as seizures, vestibular disease, or brain tumors, can cause involuntary shaking and behavioral changes in older dogs, including a loss of appetite.
Anxiety or stress
Even in old age, dogs can experience anxiety, especially from environmental changes such as a new home, loud noises, the loss of a companion, or visits to the vet.
Shaking is a classic sign of stress in dogs, and when combined with stress-induced nausea or discomfort, it may cause them to stop eating.
Older dogs can be more emotionally sensitive and may take longer to recover from emotional trauma or sudden change.
Some may also become more confused or fearful, which can contribute to behavioral symptoms like not eating and trembling.
Related: Old dog shaking and not eating but drinking water (Here’s why)
Cold or hypothermia
As dogs age, their ability to regulate body temperature may decrease.
An old dog shaking and not eating could simply be feeling cold or suffering from mild hypothermia.
This is especially true for small breeds, dogs with thin fur, or those in cooler climates.
If their bed is near a draft or if they’ve recently gotten wet, the chill may cause trembling and a loss of appetite due to discomfort.
Toxins or poisoning
Senior dogs may still chew or eat toxic substances, especially if their cognitive functions are declining.
Accidental poisoning from human medications, household cleaners, spoiled food, or plants can cause vomiting, tremors, seizures, and appetite loss.
A dog exposed to toxins will often show signs like shaking, diarrhea, drooling, or difficulty walking.
If your old dog is shaking and not eating and has been near potential toxins, seek emergency care right away.
Related: Old dog not eating and shaking and lethargic (Here’s why)
Side effects of medication
Older dogs are often on long-term medications for arthritis, heart disease, or other chronic conditions.
Some medications can have side effects like nausea, weakness, or neurological changes that may cause an old dog to tremble and avoid eating.
If symptoms appear shortly after starting or changing medication, the treatment plan may need to be reassessed.
What to do if your old dog is shaking and not eating
If your old dog is shaking and not eating, here are some steps you can take:
Observe closely for additional symptoms
Check for vomiting, diarrhea, limping, bloating, coughing, or unusual behavior.
These clues can help you and your vet understand what might be going wrong.
Check for a fever or cold exposure
Feel their ears, paws, and body to see if they’re too hot or cold.
Wrap them in a blanket if they seem cold or check with a vet if you suspect a fever.
Keep your dog hydrated
Offer water frequently. Dehydration can quickly become dangerous in older dogs.
If your dog refuses to drink, seek help promptly.
Try a bland diet
If your vet has ruled out serious illness, you may try feeding a bland diet like boiled chicken and rice to settle their stomach temporarily.
Do not force feed.
Minimize stress
Keep the environment calm and quiet.
Avoid loud noises, new pets, or major changes in routine while your dog is recovering.
Avoid self-medicating
Do not give human pain relievers or other medications without veterinary guidance—they can be toxic to dogs.
Seek veterinary care
If your old dog shaking and not eating lasts for more than 24 hours, or is accompanied by vomiting, diarrhea, disorientation, or collapse, contact your veterinarian immediately.
Older dogs can decompensate quickly and may need urgent care.
Key Takeaway
Shaking and loss of appetite in senior dogs are often signs that something deeper is going on.
Whether it’s due to pain, illness, stress, or toxins, these symptoms shouldn’t be brushed off—especially in older pets whose systems are more fragile.
Early veterinary care can mean the difference between a manageable condition and a serious emergency.
If your old dog is shaking and not eating, take action promptly to identify the cause and get them the help they need.
Your attentiveness could save their life and improve their comfort in their golden years.