The European Court of Justice (ECJ) has ruled that the Scottish Government's plan for a minimum alcohol price would breach EU law if less restrictive tax measures could be introduced.
Judges at the Luxembourg court concluded that the policy would restrict the market, which could be avoided by the introduction of an alternative tax measure designed to increase the price of alcohol.
They said it was ultimately for the national court of an EU state to determine whether other measures would be as effective in achieving the desired public health benefit.
Scotch Whisky Association (SWA) officials mounted a legal challenge alongside other European wine and spirits producers after legislation to introduce minimum pricing was passed by the Scottish Parliament in 2012.
The case will now be referred back to the Court of Session in Edinburgh for a final decision.