The scarcity of Harriers has helped to make the breed as healthy genetically as it is. Because there has never been a high demand for Harriers, breeders have always had to give careful consideration to their breeding decisions, and normally only breed the very best to the very best. Hip dysplasia is present in Harriers. Many have been diagnosed through routine OFA exams, not because the hounds were lame. Only buy from Harrier breeders who can provide you with proof of current OFA certification.
CERF testing is also highly encouraged among breeders, although eye problems are rare.
In the past, several Harriers were known to have epilepsy. Currently, however, as a result of careful breeding, epilepsy has not been seen in many years. Hounds with this problem will usually be normal at home in familiar surroundings. This is not caused by lack of socialization, because this has occurred even in hounds that were extensively socialized from a very young age. Prospective buyers should check the pups to see how they react to strange stimuli - they should be outgoing, curious and confident.