Both in theoretical and empirical studies of international trade relative prices play a dominant role. Standard international trade theory asserts that under certain conditions the price mechanism may lead to an equilibrium between demand for and supply of goods from and to different countries. For short periods, some relevant conditions may not be fulfilled; in that case other adjustments such as changes in non price conditions may equate demand and supply or, alternatively, disequilibria may exist. Direct statistical evidence on non price conditions, excess demand and excess supply is scarce.