Garlic tastes good to eat, and it's good for you — so how does it turn in to such a date-night killer after you've consumed it?
The folks at the American Chemical Society and chemistry blog Compound Interest have done the research and narrowed it down to four volatile organic compounds.
Strangely enough, none of these compounds are present in garlic until it is broken down or chopped, but when garlic's structure is damaged, enzymes convert the compound Allin to Allicin, which is responsible for the smell. Allin then breaks down in to the four compounds and one of those - Allyl Methyl Sulfide - breaks down much more slowly and as the compound gets in to your bloodstream, the only ways it can excrete are through urine, sweat, or breath.
There is a fix however - if you want to mask your garlic breath, your best options are milk, or parsley.