Can too much Selenium cause indigestion?

Generally, symptoms of too much selenium are going to be garlicky odor and hair loss. I haven't seen too many people experiencing burping and gas on selenium. But, of course, it’s possible to have random, strange reactions to different supplements. If you are on multiple supplements, you can test this by isolating your supplements one at a time. So, what you would do is maybe get off of one for a few days to see if the symptoms subside. Then, continue with another to see if you still continue having those symptoms. Otherwise, it’s really hard to tell what’s causing what.