Global drugs giant GlaxoSmithKline faces a court case for misleading advertising after two 14-year-olds found its popular blackcurrant drink Ribena contained almost no vitamin C.

I DON'T C IT: Global drugs giant GlaxoSmithKline faces a court case after two Kiwi teens found
its blackcurrant drink Ribena contained almost no vitamin C.

High school students Anna Devathasan and Jenny Suo tested the children's drink against advertising claims that "the blackcurrants in Ribena have four times the vitamin C of oranges" in 2004.

Instead, the two found the syrup-based drink contained almost no trace of vitamin C, and one commercial orange juice brand contained almost four times more than Ribena.

"We thought we were doing it wrong, we thought we must have made a mistake," Devathasan, now aged 17, told New Zealand newspapers of the school experiment.

A GSK spokeswoman in New Zealand refused to comment ahead of the case on grounds that it could affect the legal process.

Ribena, first made in the 1930s and distributed to British children during World War 2, is now sold in 22 countries.

GSK paid little attention to the claims of Devathasan and Suo until their complaints reached the Commerce Commission.

But it now faces 15 charges related to misleading advertising in an Auckland court, risking potential fines of up to $NZ3 million.