  We demonstrate that four top-quark production is a powerful tool to constrain
the top Yukawa coupling. The constraint is robust in the sense that it does not
rely on the Higgs boson decay. Taking into account the projection of the
$t\bar{t}H$ production by the ATLAS collaobration, we obtain a bound on Higgs
boson width, $\Gamma_H\leq 3.1~\Gamma_H^{\rm SM}$, at the 14 TeV LHC with an
integrated luminosity of $300~{\rm fb}^{-1}$. Increasing the luminosity to
$500~{\rm fb}^{-1}$ yields $\Gamma_H\leq 2.1~\Gamma_H^{\rm SM}$.
