Liver disease can influence the metabolism of various other organs. Regarding the influence of liver diseases on muscles, only a few studies done on people exist. The goal of our study was to investigate the influence of liver diseases on muscles in dogs. Twenty-eight dogs with different liver diseases were investigated in this study. The diagnosis of muscle alteration was based on electromyography (EMG), creatine kinase serum activity, 3-methylhistidine serum concentration and a muscle biopsy in some cases. Our results suggest that liver diseases in dogs can be accompanied with muscle alteration. 3-Methylhistidine serum concentration as a new parameter for muscle destruction in dogs was significantly increased compared to clinical healthy dogs and was comparable to those concentrations in dogs with histologically confirmed myopathy of different types. The differentiation of the liver diseases into severe hepatitis, moderate hepatitis and liver tumours showed a significant elevation of 3-methylhistidine serum concentration in cases of liver tumours (P=0.03) and a tendency in cases of severe hepatitis (P=0.07). Based on our study we can conclude that liver diseases have an influence on muscles in dogs and 3-methylhistidine could be a useful parameter for muscle destruction.