Medical journals are an extension of the marketing arms of drug firms, says an ex-British Medical Journal editor.
Dr Richard Smith, who edited the BMJ for 13 years, criticised the journals' reliance on drug company advertising.
Writing in Public Library of Science Medicine, he also said journals were undermined by relying on clinical trials funded by the drugs industry.
The BMJ said a debate was needed, but drug industry representatives rejected the criticisms.
Dr Smith, who is now chief executive of healthcare firm UnitedHealth Europe, said the most conspicuous example of the dependence was reliance on advertising, but he added it was "the least corrupting form of dependence" since it was there for all to see.
Dr Smith said the publication of industry-funded trials was a much bigger problem.
"Fortunately from the point of view of the companies which fund these trials - but unfortunately for the credibility of the journals who publish them - they rarely produce results that are unfavourable to the companies' products."
He said editors are put under further pressure by the demands of producing a profit.
"An editor may thus face a frighteningly stark conflict of interest - publish a trial that will bring in $100,000 (�54,000) of profit, or meet the end of year budget by firing an editor."
He said there needed to be more publicly-funded trials - about two thirds are currently paid for by the industry - or journals should stop publishing such trials.
"On the one hand we are saying clean up your act, while we are fairly dependent on the advertising for our survival.
"What we need now is a debate about the issue."
But Richard Ley, of the Association of the British Pharmaceutical Industry, said his criticisms were unfounded.