Seizures are a common neurological problem in both dogs and cats. When no underlying cause of the seizures can be identified, the seizures are classified as idiopathic epilepsy. In the treatment of epilepsy in dogs, there are few effective medications. The medications that are used most frequently in dogs with idiopathic epilepsy are phenobarbital and potassium bromide. Phenobarbital causes side effects such as liver toxicity, apparent changes in thyroid function, and decreased production of some types of blood cells. Potassium bromide does not cause liver or blood cell toxicity, although a recent study suggested that pancreatitis may be more common in dogs that are treated with potassium bromide and phenobarbital in combination than with phenobarbital alone. However, it was unclear whether the pancreatitis was a direct result of potassium bromide. Serum amylase and lipase activities were used in that study to diagnose pancreatitis. Elevated serum amylase and lipase activities may be seen with several diseases other than pancreatitis. A new test, serum cPLI concentration, has recently been shown to be both highly sensitive and specific for canine pancreatitis. Since pancreatitis is a potentially life-threatening disease, it is important to determine whether potassium bromide treatment is associated with an increased incidence of pancreatitis. This study will determine whether dogs with epilepsy and treated with potassium bromide develop abnormally high elevations of cPLI, a serum marker for pancreatitis, compared to dogs with epilepsy treated with phenobarbital.