See what happens when teenagers are let loose? The big drugmaker was tagged by a New Zealand court after pleading guilty to misleading consumers about the vitamin C content of its Ribena blackcurrant drink. The company was also ordered to run corrective ads in newspapers, according to the nation’s Commerce Commission.

The issue surfaced after two 14-year-olds tested their Ribena as part of a science project to see if ads claiming higher levels of vitamin C than oranges were true. The claims about Ribena constituted a “massive breach of trust with the New Zealand public,” commission chairwoman Paula Rebstock said. “As a multinational company specializing in pharmaceuticals and health products, they should have had robust testing and quality assurance systems in place.’

The court ruling comes a week after Australia’s regulator, the Australian Competition and Consumer Commission, ordered Glaxo to stop making “any express or implied representation” that Ribena contained more vitamin C than orange juice products, and to publish notices on its Web site and at stores advising consumers of the misleading statements about vitamin C.

Glaxo’s consumer health care division, which distributes Ribena, the Horlicks-brand drink and Nicorette anti-smoking chewing gum, said it regretted any confusion caused in New Zealand. “The fact that some of our products had incorrect labeling is to us, unacceptable, and we sincerely regret any confusion caused to customers who feel they may have been misled,” the company said in a statement e-mailed to Bloomberg.

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