A class action lawsuit launched in Auckland today questioning Johnson and Johnson cold and flu products follows similar suits worldwide.

JGA Saddler has filed a suit in the High Court, claiming the producer knowingly sold an ineffective product.

The US Food and Drug Administration has ruled a key ingredient in Codral, Sudafed, and Benadryl cold and flu products is ineffective when taken orally.

JGA Saddler director, Rebecca Jancauskas says it's sparked a wave of legal action.

"Our firm filed a claim in Australia, in December. A Canadian firm filed a class-action about 12 months ago, and there's also quite a number of claims on foot in America." 

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