A middle aged woman, previously healthy with the exception of mild seasonal asthma was presented with signs of acute hepatitis. The further investigation showed acute hepatitis E virus infection associated with autoimmune thyroiditis. Treatment was started with propranolol and carbimazol whereupon hepatitis and hyperthyroidism resolved. The authors think that the observed association of acute hepatitis E virus infection and autoimmune thyroiditis suggests a role of hepatitis E virus as putative trigger of autoimmune thyroiditis. The alternative possibility of thyroid dysfunction due to pre-existing autoantibodies cannot be completely excluded but seems to be unlikely given the very mild course of seasonal asthma in this patient.