Water from the English Channel is being bottled and sold as a remedy for blocked noses in the US.
Pharmaceutical experts are charging £10 for the water from a busy shipping lane off the coast of Saint Malo.
Drugs company Shering-Plough says its Afrin PureSea Hydrating Nasal Rinse is 'the only nasal rinse product made of 100% purified seawater'.
Shering-Plough says the water has been proven to clear mucus and help people breathe more easily.
A spokesman for the French company Goeman, which extracts the water, told the Mail that the water was collected several kilometres off the coast for purity and had to meet strict quality controls.