Tudca Side effects
Tauroursodeoxycholic acid (also known as TUDCA) is an ambiphilic bile acid. It is the taurine conjugate form of ursodeoxycholic acid. Humans are found to have trace amounts of TUDCA.
There are no know side effects of supplementing with TUDCA and many studies proving its beneficial properties for the liver and general health.
Usage of 500mg TUDCA daily for one year (in persons after liver transplants) was not assocaited with any adverse effects  and in otherwise healthy obese persons doses of 1,750mg have been well tolerated for up to 4 weeks. 
In persons with primary biliary cirrhosis, 750mg daily for 2 months was not associated with any adverse effects  and a similar population was able to tolerate 1,500mg daily for 6 months with no adverse effects. 
TUDCA is generally safe for its users as long as it is taken with care and caution. There are no listed side effects of TUDCA because it is naturally produced in the body and it plays a key role in protecting the liver as well as digesting and absorbing essential vitamins and minerals that are needed by the body.