If you end up with garlic breath that never goes away, you have ingested too much selenium.
The old mineralogy texts/references have a "taste" test. Selenium was rated as a "garlic" taste.
I know a guy who used to work with Seleniun compounds. He told me the above. He also told me he was never around when they would first open the quartz tubes containing his crystals.
Matt
http://www.sciencestuff.com/msds/C2450.html