Drug property of Femannose – manufacturers of borderline products must be careful

Femannose is a functional drug – pharmacological action makes the difference.

With its decision "Femannose II" (BGH, Urt. v. 9.10.2025 – I ZR 4/21) the Federal Court of Justice (BGH) puts the final full stop to one of the most prominent borderline product disputes of recent years. As early as spring 2025, the Court of Justice of the European Union (EuGH) had established that D-Mannose exerts a pharmacological action. We have already reported on this judgment:EuGH had in spring 2025 established that D-Mannose exerts a pharmacological action. We have already reported on this judgment:

Pharmacological action – drug or medical device?

The BGH builds on this and now confirms definitively: the Femannose product at issue is a functional drug, not a medical device. Femannose product is a functional drug, not a medical device.

The path to the decision was long: the Regional Court (LG) Cologne granted the claim of a competition association, the Higher Regional Court (OLG) Cologne confirmed this, the defendants appealed in revision – whereupon the BGH referred the famous preliminary ruling question ("Femannose I") to the EuGH. After the clear answer from Luxembourg, the path was now clear for the national decision. The BGH rejects the appeal in full. LG Köln granted the claim of a competition association, the OLG Köln confirmed this, the defendants appealed in revision – whereupon the BGH referred the famous preliminary ruling question ("Femannose I") to the EuGH. After the clear answer from Luxembourg, the path was now clear for the national decision. The BGH rejects the appeal in full.

What exactly was at issue: product concept and initial conflict

The defendant distributes the preparation Femannose®, originally a combination of D-Mannose and cranberry extract, for the treatment and prevention of urinary tract infections. Since 2017, distribution of the further developed product Femannose® N, which contains exclusively D-Mannose, has taken place. Both products were placed on the market and advertised as medical devices.

The claimant competition association contended that these were in fact pharmaceuticals requiring approval. Since pharmaceutical approval was not obtained, both distribution and advertising were unlawful.

The BGH follows this argumentation completely.

Legal considerations: Why Femannose is a functional drug

Pharmacological action: confirmation of the EuGH line

The BGH adopts the core statement of the EuGH almost word-for-word: D-Mannose binds reversibly to bacterial FimH adhesins and thereby prevents their attachment to the human bladder wall. This blockade constitutes a pharmacological action. The interaction need not take place at human cells; an interaction with bacteria present in the body is sufficient.

It is also irrelevant that the binding occurs only reversibly – the BGH explicitly follows the broad concept of action established by the EuGH.

Overall assessment: presentation, application and product character

The BGH states that pharmacological action alone does not necessarily lead to classification as a drug. However, it confirms the careful overall assessment of the OLG Cologne: Femannose is offered in a pharmaceutical-type dosage form with package insert, detailed information on dosage, application and side effects, and it is used for the treatment of a specific disease. The considerable market distribution also played a role.

This overall assessment speaks unequivocally for classification as a {

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