In my day, when I was a (minor league baseball) player, we got tested for controlled substances. But everybody knew how to beat the test. All you had to do was drink a cup of white vinegar. Back then, they just did the urine test. They didn't have the blood test. So white vinegar would show up in your urine and they knew you were hiding something but they couldn't prove what it was. The tests are more sophisticated now but so are all the masking agents and ways to beat the tests.
— Eddie Bonine
BaseballDay