King Charles Spaniel: inherited diseases and health

Updated 2026-09-30 · 2 sources

Based on: OMIA (University of Sydney), Wikidata

Breed health

The inherited conditions below have been documented in this breed in published research. That does not mean your dog has them or will get them – but it helps to know the names when you talk to a breeder or a vet.

King Charles Spaniel and chocolate: how much is dangerous?

Typical adult weight: 3.6–6.3 kg. Grams of chocolate at which signs can start (20 mg/kg) and at which severe signs are reported (40 mg/kg):

Dog weight	Milk	Dark 70–85%	Baking / unsweetened
3.6 kg	36 g signs 72 g severe	9.0 g signs 18 g severe	5.1 g signs 10 g severe
6.3 kg	63 g signs 126 g severe	16 g signs 32 g severe	9.0 g signs 18 g severe

Based on published doses: signs from about 20 mg/kg, severe signs from 40 mg/kg (US FDA, Cortinovis & Caloni 2016, Swedish Poison Information Centre). An estimate, not a diagnosis.

Check the exact amount with the chocolate calculator →

Inherited conditions documented in the breed

Conditions documented: 3

Condition	Body system	Inheritance	Gene variant known
Budd-chiari syndrome^[1]	Cardiovascular system	–	–
Chiari malformation Type I with syringomyelia^[1]	Nervous system	Multifactorial	No
Patellar luxation^[1]	Limbs / fins / digit / tail	Multifactorial	No

What this list means

“Documented in the breed” means at least one published case or study – it says nothing about how common the condition is.
Many of these conditions are rare. A responsible breeder can tell you which health tests the parents have had.
Where the gene variant is known, a DNA test may exist – ask your vet or the breed club.
If your pet shows signs of illness, contact your vet. This page cannot tell you whether your pet is ill.

About the breed

Weight: 3.6–6.3 kg
FCI number: 128

^[2]

If your pet is struggling to breathe, has collapsed, is having a seizure or can't stand up: go to the nearest vet now.

Not sure how serious it is?

OkPaw asks a few quick questions about your pet and tells you in 30 seconds whether it can wait. Free on Google Play for Android.

OkPaw is on Android now – an iPhone version is on its way.

Sources

How this page was made: the list is taken directly from the sources below; nothing on it was written by AI. Names of conditions may be machine-translated. It is information, not a diagnosis. How we write our pages