Plant-based foods cannot be sold in the European Union using terms such as milk, butter and cheese, the European Court of Justice has ruled.
The ECJ was ruling in a case referred to it by a German court and involving German food company TofuTown.
The company sells plant-based products with names including "Soyatoo Tofu Butter" and "Veggie Cheese".
It said customers were not misled, because their products' plant origins were clear.
Since December 2013 EU regulations have stated that designations such as milk, butter, cheese cream and yogurt can only be used for marketing and advertising products which are derived from animal milk.
There are some exceptions. Coconut milk is allowed, for example, as are peanut butter, almond milk and ice cream.
However, soya and tofu are not exempted.
In the case of TofuTown, German consumer protection group VSW, which aims to combat unfair competition, complained that the product names broke EU law.
The VSW went to the regional court in Trier in a bid to stop the company describing its soya and tofu products as milk or cheese.
TofuTown argued that its advertising did not infringe the EU legislation and so the court asked the ECJ to intervene.
The ECJ ruled that the designations like milk and cheese could not be legally used for purely plant-based products: "The addition of descriptive or clarifying additions indicating the plant origin of the product concerned, such as those used by TofuTown, has no influence on that prohibition."
It is up to national courts to enforce EU laws and this case will now return to the court in Trier.
A consumer group or other organisation could bring a similar complaint about dairy-style names in the UK or anywhere else in the EU.
"What's interesting is that the court here has interpreted the law very strictly," says Katie Vickery, a partner with law firm Osborne Clarke.
"There has been a lot of growth in the sale of these kinds of products in recent years. There's a consensus that customers obviously understand what they are buying - and firms may have thought they could get away with it.
"This ruling suggests otherwise."
In the longer term, it would be possible for the European Commission to amend the law to extend the number of exceptions and make it permissible to give soya and tofu products names like milk and butter.