Health

As a consequence of selective breeding, French Bulldogs are disproportionately affected by health related problems:

Brachycephalic airway obstructive syndrome
The skull malformation brachycephaly was increased by breeding selection which led to the occurrence of the brachycephalic airway obstructive syndrome. Therefore many French Bulldogs often pant sticking out their tongue even at slight efforts like walking. The brachycephalic syndrome causes them to have multiple side effects, as in difficulty breathing (which includes snoring, loud breathing). It happens because they have narrow nostril openings, a long soft palate, and fairly narrow tracheas. This issue can lead to death in French Bulldogs if they are not undergoing proper treatment.

In order to treat these dogs and create a smoother airway to the lungs, a procedure must be done that takes out a portion of their soft palate. The results of the procedure show a minimum of 60% better airway passage to the lungs.

In 2013, a UK Medical Study reviewed the health of 2228 French Bulldogs under veterinary care in the UK. The study found that 1612 (72.4%) of these French Bulldog had at least one recorded health issue: "The most common disorders recorded were ear infections (14.0%), diarrhea (7.5%) and conjunctivitis (3.2%). Skin problems were the most commonly reported group of disorders (17.9%). This study of over two thousand French Bulldogs provides a framework to identify the most important health priorities in French Bulldogs in the UK and can assist with reforms to improve health and welfare within the breed."

Temperature regulation-related issues
The French Bulldog has only a single short coat, which combined with their compromised breathing system, makes it impossible for them to regulate their temperature efficiently. This means the dog may easily become cold, and are prone to heat stroke in hot and humid weather. French Bulldogs are also prone to allergies, which can cause eczema on the body.

As they are a brachycephalic breed, French Bulldogs are banned by several commercial airlines due to the numbers that have died while in the air. This is because dogs with snub noses find it difficult to breathe when they are hot and stressed. The temperature in a cargo space in an aircraft can rise as high as 30 °C (86 °F) when waiting on the runway.

Birth and reproduction
French Bulldogs sometimes require artificial insemination and, frequently, Caesarean section to give birth, with over 80% of litters delivered this way.

Back and spine
French Bulldogs are prone to having congenital hemivertebrae (also called "butterfly vertebrae"), which will show on an X-ray.

In October 2010, the UK French Bulldog Health Scheme was launched. The scheme consists of three levels: the first level, Bronze, designates a basic veterinary check which covers all the Kennel Club Breed Watch points of concern for the breed. The next level, Silver, requires a DNA test for hereditary cataracts, a simple cardiology test, and patella grading. The final level, Gold, requires a hip score and a spine evaluation. The European and UK French Bulldog fanciers and Kennel Clubs are moving away from the screw, cork-screw or 'tight' tail (which is an inbreed spinal defect), and returning to the short drop tail which the breed originally had. The UK breed standard now states that the tail should be "undocked, short, set low, thick at root, tapering quickly towards tip, preferably straight, and long enough to cover anus. Never curling over back nor carried gaily."

The French Bulldog may develop skin fold dermatitis.

Health

Curvature of the back, called roaching, might be caused by patella problems with the rear legs, which in turn causes the dog to lean forward onto the forelegs. This might also just be a structural fault with little consequence to the dog. Due to their shortened muzzles, many Boston Terriers cannot tolerate excessively hot or cold weather and demanding exercise under such conditions can cause them harm. A sensitive digestive system is also typical of Boston Terriers with flatulence commonly being associated with poor diet in the breed.

Their large and prominent eyes make Boston Terriers prone to corneal ulcers. Due to the breed being characterized by a short muzzle paired with a large pair of eyes, their eyes are susceptible to injury when making contact with sand, dust, debris, or sharp objects, such as plants with thorns.

Boston Terriers are brachycephalic breeds. The word comes from Greek roots "Brachy," meaning short and "cephalic," meaning head. This anatomy can cause tiny nostrils, long palates and a narrow trachea. Bostons may be prone to snoring and reverse sneeze—a rapid and repeated forced inhalation through the nose—accompanied by snorting or gagging sounds used to clear the palate of mucus, which does not harm the dog if it does not last for more than 1–2 minutes. Brachycephalic dogs may be prone to complications with general anesthesia. Bostons frequently require caesarean section to give birth, with over 80% of litters in a UK Kennel Club survey delivered this way.