How does certo help with drug tests?

Terribly. The idea is, if you take Certo you'll pee more, and this will dilute the drugs in your urine. The problem is, pectin pulls MORE drug metabolite out of your body into your urine...so instead of having a metabolite quantity in your urine that's too low to be detected, you wind up with more of it in your urine. Certo is for making jelly. Unless you want to do that, don't get Certo.