The trial is a multi-center (Malmö and Stockholm), controlled, single-blind design and the subjects are randomised to thyrostatics with and without diclofenac by a body independent from the study The total duration of the study is 24 months with 12 months treatment with or without diclofenac in addition to regular treatment for thyrotoxicosis. The follow up period will be 12 months. Decision of the main treatment of thyrotoxicosis is based on clinical terms according to routines in Malmö and Stockholm and is given according to the protocol of TT96. Patients are randomised for adjuvant therapy with or without diclofenac after choice of main treatment for thyrotoxicosis.