KEY POINTS:
A high school science experiment by two 14-year-old girls has embarrassed the world's second-largest food and pharmaceutical company.
GlaxoSmithKline will appear in Auckland District Court on Tuesday to face charges alleging 15 breaches of the Fair Trading Act.
The charges, brought by the Commerce Commission, arose from an investigation by Pakuranga College students Anna Devathasan and Jenny Suo into the vitamin C levels of the popular Ribena drink, which has sales of about $8 million a year.
The company faces a maximum fine of $200,000 on each charge.
GSK has a worldwide turnover of more than $61 billion, second only to drug giant Pfizer.
The students - now 17 - decided in mid-2004 to test the vitamin C levels of their favourite juices, including Ribena, Just Juice and Arano, for a school project.
They calculated that each 100ml of Ribena contained about 22mg of vitamin C.
Just Juice products contained levels of about 72mg.
The figure for Ribena seemed too low, particularly as the company had promoted the product by claiming that blackcurrants had four times the vitamin C of oranges.
"We thought we were doing it wrong, we thought we must have made a mistake," Anna said.
The girls got short shrift when they took their observations to GlaxoSmithKline.
In a letter, the girls described its advertising as "intentionally misleading and quite inappropriate".
When they got no response, they telephoned the company.
"They didn't even really answer our questions. They just said it's the blackcurrants that have it, then they hung up," Jenny said.
Undeterred, the girls contacted the Advertising Standards Authority, and Brandpower, but still got no satisfaction.
But then the television consumer affairs show Fair Go picked up the story and suggested the girls take their findings to the Commerce Commission.
The pair put the matter out of their minds, until the prosecution made the news about a month ago.
"It's completely unbelievable," Jenny told the Weekend Herald yesterday.
"It's pretty crazy when you realise how much power you can have, as a kid as well."
The girls have since visited the company to be thanked "for bringing it to our attention".
GSK's TV advertisements claimed "the blackcurrants in Ribena have four times the vitamin C of oranges". The commission said that although blackcurrants had more vitamin C than oranges, the same was not true of Ribena.
It also alleged its testing found ready-to-drink Ribena contained no detectable level of vitamin C.
The girls' discoveries have also scored a hit in Australia.
GSK Australia this week dobbed itself into the Australian equivalent of the Commerce Commission, admitting it had been misleading in its Ribena claims.
The case
* Testing found ready-to-drink Ribena contains no detectable vitamin C.
* The Commerce Commission said television advertising claims about the amount of vitamin C in Ribena were misleading.