The object of this study is to unravel the role of the faecal microbiome in the pathophysiology of canine idiopathic epilepsy and to examine the effect on faecal microbiome and the epileptic seizure control of two therapeutic strategies, namely 1) ketogenic diet enriched with medium chain triglycerides (MCT) and 2) faecal transplant in drug-resistant canine idiopathic epilepsy. First, the faecal microbiome in healthy dogs, dogs with drug-sensitive idiopathic epilepsy and dogs with drug-resistant idiopathic epilepsy will be examined. The gut microbiota composition will be screened but also their activity and function will be estimated by analysing metabolome (function and activity) and metagenome (composition) and linking those results. Second, a 3-month prospective, randomised, double-blinded, placebo-controlled dietary trial with a complete MCT-included diet will be performed. Outcome variables include faecal microbiome and metabolome, epileptic seizure control and quality of life. Third, the effect of faecal microbial transplant from healthy donor dogs on dogs with drug-resistant idiopathic epilepsy will be examined using the same outcome variables.