Experienced and professional animal trainer provide their insights in answering this question :
A. It can be caused by very painful eye condition like injury ( it can be not visible with “naked” eye), glaucoma. See your vet to check what is going on and start proper treatment.

How to Identify Common Pet Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced pet care professionals :

Infections, illnesses, and pain can make your dog tired, listless and uninterested in food. When these symptoms continue for more than 24 hours, they could indicate the presence of a health issue that requires a visit to our veterinary hospital in Diamond Bar.
Bladder infections or urinary tract infections are two major culprits of reduced thirst. It could also be diabetes or kidney disease. If you notice other symptoms like lethargy and lack of appetite, and feel like something might be wrong, it`s important to call your veterinarian and discuss what`s going on.
Anything that can cause a dog to feel ill, such as kidney disease, pancreatitis, intestinal parasites, liver disease, cancer, infection, intestinal obstruction, etc., can lead a dog to refuse food and water. Like humans, dogs cannot go for more than a few days without water, so this should be treated seriously.
Potential causes include inner/middle ear infections, intoxication, strokes, tumors, infectious or inflammatory diseases (meningitis), idiopathic vestibular disease (also called “old dog” vestibular syndrome), or other less likely causes.
Some of the signs of parvovirus include lethargy; loss of appetite; abdominal pain and bloating; fever or low body temperature (hypothermia); vomiting; and severe, often bloody, diarrhea. Persistent vomiting and diarrhea can cause rapid dehydration, and damage to the intestines and immune system can cause septic shock.
What are the symptoms of canine distemper? Initially, infected dogs will develop watery to pus-like discharge from their eyes. They then develop fever, nasal discharge, coughing, lethargy, reduced appetite, and vomiting.
Monitor your dog for additional symptoms, such as lack of appetite, abdominal pain, vomiting, diarrhea, lameness, or straining to urinate. If you notice significant alterations in your dog`s behavior or additional symptoms, contact a licensed veterinarian.
The clinical signs of more advanced kidney failure include loss of appetite, lethargy, vomiting, diarrhea, and very bad breath. Occasionally, ulcers will be found in the mouth.
Healthy dogs can typically survive up to five days without eating, but only if they have access to drinking water. In extreme situations, dogs have been known to survive without sustenance for much longer, but not without any severe health consequences.
The word ataxia means incoordination within the nervous system. The abnormal movement can occur in the legs, the head, the torso, or all three. There are several different forms of ataxia, depending on where in the nervous system the abnormality occurs.
Neurological conditions such as seizures, viruses (such as Distemper) can cause your dog to act scared and shake. Neurological conditions cause involuntary shaking and seizing which can be very scary for your dog and cause them to show fear and to shake uncontrollably.
The first sign of parvo for puppies is often lethargy, lack of appetite, and a fever. Canines will begin to suffer from vomiting and diarrhea as the virus progresses, and can experience dehydration and a high heart rate as a result.
Parvo smell has a unique very bad-smelling poop that is not easy to forget. The smell has been described as metallic, with hints of blood stench since the virus affects the intestinal walls, and a seemingly sweet scent.
Symptoms caused by swallowed poisons can include: vomiting, diarrhoea, agitation and heart issues. Inhaled toxins may cause breathing difficulties or loss of consciousness in dogs. If your dog`s skin comes in contact with a poisonous substance typical symptoms include irritation and pain.
Common Signs of Dog Poisoning

The following may be signs of dog poisoning: Diarrhea or blood in the stool (either bright red blood or dark black tarry stools) Vomiting or loss of appetite. Seizures or tremors.

Leptospirosis is a bacterial disease of dogs and other mammals that primarily affects the liver or kidneys. The bacteria (Leptospira) that cause leptospirosis, commonly called leptospires, thrive in water and have a helical or spiral shape with a characteristic hook on one or both ends.
`Kennel Cough` is the term that was commonly applied to the most prevalent upper respiratory problem in dogs in the United States. Recently, the condition has become known as tracheobronchitis, canine infectious tracheobronchitis, Bordetellosis, or Bordetella. It is highly contagious in dogs.
Canine adenoviruses (CAVs) and canine herpesvirus (CHV) are pathogens of dogs that have been known for several decades. The two distinct types of CAVs, type 1 (CAV-1) and type 2 (CAV-2), are responsible for infectious canine hepatitis (ICH) and infectious tracheobronchitis (ITB), respectively [1], [2].
There are several reasons that could be causing your dog to appear tired and listless. The most common causes of lethargy in dogs are: Infection, including parvovirus, distemper, kennel cough and leptospirosis. Metabolic diseases, such as heart problems, liver problems, diabetes, and hypoglycaemia.
Vestibular syndrome refers to a group of diseases that affect the balance system (also known as the vestibular system). Common signs of vestibular syndrome in dogs and cats include loss of balance, falling, rolling over, abnormal flickering of the eyes and general wobbliness.
Lethargy is a common sign of illness. When your dog doesn`t feel well, he may have a decreased energy level. Any behavior that is unusual for your dog, such as hiding, listlessness or pacing, difficulty breathing, or trouble walking, merits a call to your veterinarian.
Although a loss of appetite in dogs doesn`t necessarily indicate serious disease, prompt veterinary attention is important because it could be a sign of significant illness, including cancer, various systemic infections, pain, liver problems, and kidney failure. Dental disease.
The most common scenario in which a dog develops pancreatitis is after eating a relatively high-fat meal, such as barbecue meat or a holiday ham. The clinical symptoms typically begin within the next 12 to 24 hours.
Pancreatitis in dogs is an inflammatory reaction within the pancreas that can result in abdominal pain, inappetence, and vomiting. The inflammation results from the inappropriate, early activation of an enzyme within the pancreas, which causes the pancreas to digest itself.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Q. My dog doesn’t seem to be drinking, what should I do?
ANSWER : A. If it has been this way for a long time and your dog seems otherwise healthy (eating, active), he/she may be getting water from other sources, such as wet food, outside, or the toilet. I would try to identify other sources they could be getting it from first. If the dog is truly not drinking or not getting moisture from wet food or other sources, he/she may need to be examined by a veterinarian.
It is more concerning if a dog suddenly stops drinking, especially if he/she also stops eating. This can be a starting sign of almost any illness and definitely warrants veterinary attention. If the dog is still drinking some, and still eating and active, there may be a less serious reason for the change. For instance, cooler temperatures, food changes, and decreased activity can cause decreased water intake.

Q. Why does my dog eat grass?
ANSWER : A. As another user mentioned, dogs can eat grass when they want to vomit. Sometimes, when a dog has an upset tummy, they will eat grass. If you notice your dog eating grass frantically, you can assume vomiting will shortly follow. Grass does not digest and pass normally. If your dog eats too much grass, it can cause serious issues with pooping. Your dogs poop can end up all tangled inside of her, and it can need veterinary assistance to remove it. The same goes for celery, so avoid feeding celery to your dog.

The other day my boyfriend accidentally left the laundry room door open where we were keeping the trash that was filled with cooked chicken bones. She ate one of the chicken bones lightning fast. We had to induce vomiting by feeding her some hydrogen peroxide. After we had fed her the peroxide, she immediately began frantically eating grass because her tummy was upset.

If there is something lacking in your dogs diet, it could be that your dog is eating grass to make up for it. I am sure that my dogs diet is extremely well balanced (I do not only feed her an air-dried raw food-type diet (Ziwipeak), but a wide variety of safe, healthy foods), so when she eats grass, I know that it is because she has an upset tummy.

That is why I think it is important making sure your dog has a very well balanced diet. If your dog is on a low quality kibble, your dog may be trying to let you know by eating grass (or eating poop).

Q. My dog recently stopped eating after he was overfed by mistake, he seems fine, he is still drinking but refuses to eat. Its been nearly 48 hours now.
ANSWER : A. Overeating may have caused some digestive upset, which is causing him to not eat, however overeating may also cause a serious condition called bloat. Bloat symptoms include a large bloated abdomen that may be painful to the touch, labored breathing or panting, attempting to vomit or defecate without success, refusal to eat, and pale or blue tongue and gums. If you see these signs, then immediate veterinary care is needed. If your dog seems otherwise fine except for not eating, you can try to entice him to eat and settle minor upset stomachs with a meal of boiled rice and chicken, however if he has not eaten in over 48 hours it is best to seek veterinary care as a more serious problem could be underlying.

Read Full Q/A … : When to put a dog to sleep

Q. My dog hasnt eaten snce I left 4 days ago. I won’t be home for 6 more days. How can the caretaker get her to eat?
ANSWER : A. If your dog is feeling a bit sad while you are away and is refusing to eat, your pet sitter may try some things such as adding in boiled chicken or turkey to meals to encourage eating. A pet-safe gravy may also entice your dog to eat as well while you are gone. Your pet sitter may also want to offer smaller meals more often throughout the day to give your dog more chances to try and eat when she is feeling more comfortable and a little less sad. A game of fetch or playing together may also get your dog’s appetite going and help her to feel more comfortable eating around your pet sitter.

If your dog is showing any other signs of illness in addition to the refusal to eat (beyond normal missing an owner), then it is always a good idea to keep an eye out and contact a veterinarian as needed.

Read Full Q/A … : ufdc.ufl.edu

Q. Sudden eye soreness, lethargy, and refusal to eat/drink in an otherwise VERY lively and active puggle.
ANSWER : A. It can be caused by very painful eye condition like injury ( it can be not visible with “naked” eye), glaucoma. See your vet to check what is going on and start proper treatment.

Q. Weak, discharge from eyes, swelling on right eye, does not want to open eyes. What is wrong?
ANSWER : A. If the discharge from the eye is green or yellow in color, it can indicate a secondary infection. Swollen eyes can be caused by a number of things ranging from allergies to infections, to injury to the eye itself or surrounding areas.

It is best to have your pet’s eye examined by your local vet. They will most likely wish to place a stain in the eye that can check for damage such as cuts or scratches. An ointment can then be given to help reduce inflammation, pain and take care of infection.

Until you can get to the vet, be sure to not let your pet scratch or paw at their eye as this can make things worse. You can also use a warm wet washcloth to gently remove any debris and allow the eye to open some, providing relief. However, if symptoms worsen, or the swelling travels to the face, head or neck, it may indicate a serious allergic reaction which should be treated immediately.

Q. My pet is suffering eyes discharge, what should I do?
ANSWER : A. Mucus, yellow-green pus, or a watery eye discharge can all be signs of conjunctivitis, which is inflammation of the lining of your dog’s eye.

There is a wide range of causes for conjunctivitis, from allergies, injury, birth defects, and tear duct problems, to foreign bodies, dry eye syndrome, infections or even tumors.

Other signs of conjunctivitis include excessive blinking or keeping the eye closed, squinting and pawing at the eyes.

Treatment of this condition depends on the underlying cause. In most of the cases cleaning, soothing the eye and applying antibiotics eye drops suffice but is some instances further investigation is required to establish the cause of the excessive eye discharge, and this should be performed by a veterinarian.

Q. Why do dogs eat grass?
ANSWER : A. Some pet parents get concerned when they see their favorite canine nibbling on grass in the yard. They wonder whether it is because hunger, boredom or an indication of an underlying illness. Often the consumption of grass will result in vomiting because it irritates the stomach and gastrointestinal tract. This is an extremely common problem for dog parents. There is no one reason for why dogs exhibit these behaviors and it is very much dependent on each dog. Here are some of the reasons why our dogs choose to eat grass:

1. Nutritional Issues

Historically speaking, dogs are considered omnivores, which mean they consume a variety of both meat and plant-based food. There is some indication that dogs with a low fiber diet may choose to scavenge in the grass to fulfill this nutritional deficiency. These dogs may also find that grass has an appealing flavor and consistency. If you feel that this may be the reason for your beloved canine consuming grass then consider discussing with your veterinarian on how to incorporate more fiber into your dog’s diet.

2. Boredom

Many dogs who are not receiving adequate exercise will be become bored and search out activities to occupy their time, including eating grass. Evaluate how much exercise your dog is getting on a daily basis and consider more walks or other fun activities, such as playing fetch or tug of war.

3. Upset Stomach

There is a belief that dogs with an upset or gassy stomach will self-medicate by consuming grass. Vomiting often follows this grass eating activity eliminating the contents of the stomach or changing the gas distension within the gastrointestinal tract. However, there is not much scientific evidence to back up this theory. If you are concerned about too much gastric acid in your dog’s stomach or any other underlying medical issue that could be the reason for their grass eating, consult with your veterinarian.

Overall, grass eating is usually not toxic to your dogs unless your lawn contains chemicals, including pesticides or herbicides. Monitor your dog’s behavior along with his diet and exercise to determine if there is a reason for the inappropriate grass snacking.