  In this paper, we discuss the toric ideals of Minkowski sums of unit
simplices. More precisely, we prove that the toric ideal of Minkowski sum of
unit simplices has a squarefree initial ideal and is generated by quadratic
binomials. Moreover, we also prove that Minkowski sums of unit simplices have
the integer decomposition property. Those results are a partial contribution to
Oda conjecture and B{\o}gvad conjecture.
