Shih Tzus most commonly die from heart disease, digestive disorders, and age-related decline in quality of life, each accounting for roughly 8 to 10% of recorded deaths. Unlike many other breeds, cancer is a relatively minor threat, responsible for only about 10% of deaths in the smallest dog breeds including Shih Tzus. Their typical lifespan ranges from 10 to 18 years, which is longer than average for dogs overall, but several breed-specific vulnerabilities can shorten that window.
Heart Disease
Heart disease ties as the leading cause of death in Shih Tzus, found in about 8 to 10% of deaths recorded in veterinary studies. The specific condition driving this is mitral valve disease, a progressive deterioration of one of the heart’s valves that lets blood leak backward with each beat. It’s the most common heart condition in small-breed dogs generally, but Shih Tzus and Dachshunds are among the most predisposed breeds.
In a large French study of small breeds, roughly 14% of dogs had detectable heart murmurs linked to mitral valve disease, with males nearly twice as likely to be affected (18.5%) as females (9.8%). The reassuring finding: most dogs with these murmurs were in the earliest stage of disease and never progressed to full heart failure. Still, the condition worsens over time, and in some dogs it eventually leads to fluid buildup in the lungs and difficulty breathing. If your Shih Tzu develops a cough that worsens at night, tires easily on walks, or breathes faster than usual while resting, those are signs worth investigating.
Digestive and Bowel Disorders
Enteropathy, a broad term for chronic bowel disease, matches heart disease as a top cause of death at around 8 to 10%. This category covers conditions that cause persistent vomiting, diarrhea, weight loss, or inability to absorb nutrients properly. Some cases stem from inflammatory bowel disease, food sensitivities, or infections that become severe or go untreated too long.
Because Shih Tzus are small dogs, they have less physiological reserve when they stop eating or lose fluids. A bout of vomiting and diarrhea that a Labrador might shake off in a day can become dangerous for a 12-pound Shih Tzu much faster. Persistent changes in stool, unexplained weight loss, or repeated episodes of vomiting are worth taking seriously rather than waiting out.
Kidney Problems in Younger Dogs
Shih Tzus carry a breed-specific genetic vulnerability called renal dysplasia, where the kidneys don’t develop properly. One study estimated that roughly 85% of Shih Tzus in North America carry some degree of this defect, though severity varies enormously. The condition follows an autosomal dominant inheritance pattern with incomplete penetrance, meaning a dog can carry the gene without necessarily becoming sick.
In severe cases, puppies may die within months of birth from kidney failure. Dogs with moderate forms typically live one to two years before their kidneys can no longer keep up. The mildest cases may show only increased thirst and urination, and some live a full lifespan with no obvious problems. Early signs in younger dogs include drinking and urinating far more than normal, poor growth compared to littermates, and a generally unthrifty appearance. This is one reason kidney health deserves attention from the start in this breed, not just in old age.
Breathing Difficulties
Shih Tzus are a brachycephalic breed, meaning their skulls are shortened and their airways are compressed. This gives them their distinctive flat face but also predisposes them to brachycephalic obstructive airway syndrome. The condition involves narrowed nostrils, an elongated soft palate, and sometimes a narrowed windpipe, all of which make breathing harder than it should be.
Over time, the extra effort required to pull air through these narrow passages causes throat tissues to swell and thicken, making the obstruction progressively worse. This can lead to overheating (since dogs cool themselves by panting), exercise intolerance, and in acute episodes, a full respiratory crisis. Aspiration pneumonia, where food or fluid enters the lungs, is another associated risk. While breathing problems don’t top the mortality statistics the way heart or bowel disease do, they contribute to reduced quality of life and can trigger emergencies, particularly in hot weather or during anesthesia.
Cancer Risk Is Lower Than Most Breeds
One piece of genuinely good news for Shih Tzu owners: cancer kills far fewer Shih Tzus than it does larger breeds. A 2024 study from UC Riverside found that the smallest dogs, including Shih Tzus, Pomeranians, and Chihuahuas, have only about a 10% chance of dying from cancer. For comparison, some large breeds like Golden Retrievers and Bernese Mountain Dogs face cancer rates several times higher. This lower cancer risk is one factor behind the breed’s relatively long lifespan.
Age-Related Decline
A notable proportion of Shih Tzu deaths, around 8 to 10%, are attributed to “poor quality of life” rather than a single identifiable disease. This reflects the reality that many Shih Tzus live long enough to experience a gradual accumulation of problems: failing vision, arthritis, incontinence, cognitive decline, and loss of appetite. In veterinary records, about 5.6% of deaths specifically listed appetite loss or significant weight loss as the primary concern.
Spinal cord problems also appear in the top causes, accounting for roughly 5.6% of deaths. Intervertebral disc disease and other spinal conditions can cause pain, paralysis, or loss of bladder control, all of which significantly affect a small dog’s daily life.
Screening That Can Help
The breed’s parent club and the Orthopedic Foundation for Animals recommend specific health screenings. Required tests for breeding dogs include an eye examination and an evaluation for patellar luxation, a condition where the kneecap slips out of place. Optional but recommended screenings include hip evaluation and a cardiac exam, which can catch mitral valve disease before symptoms appear.
Even if your Shih Tzu isn’t a breeding dog, these same screenings have practical value. A baseline heart check by your vet can establish what’s normal for your dog, making it easier to detect changes later. Monitoring kidney values through routine bloodwork is particularly worthwhile given the breed’s predisposition to renal dysplasia. And keeping up with dental care matters more than many owners realize: Shih Tzus are prone to significant dental disease, and chronic oral infections can stress the heart and kidneys over time.
Keeping your Shih Tzu at a healthy weight, avoiding excessive heat exposure, and staying current on dental cleanings won’t eliminate breed-specific risks, but they address the conditions most likely to shorten your dog’s life.