When vitamin b1 is consumed in excess of your needs, how does the body deal with the excess?

Excreted in urine. When you take more b1 than you need your body excretes the excess in your urine, resulting in a bright yellow color & b vitamin odor. If you take b1 & this happens, it does not mean you did not need it. When you drink water much of that is eliminated in your urine, but that does not mean you did not need water or that it was not useful as it passed thru you. B1 is non-toxic- high doses don't harm.