Officials have dropped charges against pharmacies alleged to have advised people to take homeopathic remedies to protect them against malaria instead of anti-malarial drugs.
The General Pharmaceutical Council's decision has been described as "shabby and irresponsible" by some who helped bring the case against the pharmacies.
Charges were bought after an undercover investigation by campaigning group Sense about Science and BBC Newsnight.
Experts advocate anti-malaria drugs.
Speaking about the latest decision, Tracey Brown, director of Sense about Science said "we may as well have no regulation of pharmacists at all".
It comes days after the Royal Pharmaceutical Society said they were "shocked" that one of the pharmacies involved, Ainsworths in London, is still suggesting taking homoeopathic remedies to prevent serious diseases such as typhoid, polio and malaria instead of proven drugs and vaccinations.
The 2006 undercover investigation showed that homeopathic pharmacies were recommending sugar pills which include no active ingredients instead of drugs and vaccinations for travellers to countries where malaria is endemic.
At the time the head of the Royal London Homeopathic Hospital Dr Peter Fisher told Newsnight "there is absolutely no reason to think that homeopathy works to prevent malaria… people may even die of malaria if they follow this advice".
The government's Chief Scientist, Professor Sir John Beddington, recently told BBC News that "there is no scientific evidence to indicate that homeopathic remedies are efficacious and the fundamental underpinning of homeopathy seems to me to be scientific nonsense".
The pharmacists from three practices including Ainsworths were set to face fitness to practice hearings which could have resulted in them being struck off or other penalties.
Now the General Pharmaceutical Council (GPhC) has written to Sense about Science to say that it has dropped the action. It gives two reasons.
First the GPhC says that Ainsworths' pharmacist Anthony Pinkus has taken "remedial action" to prevent what happened in 2006 ever happening ever again.
However last week Newsnight showed a leaflet they were given by the pharmacy in 2010 to the Royal Pharmaceutical Society (RPS).
The leaflet advertised Ainsworths' homeopathic remedies for serious diseases and said there was anecdotal evidence that they were a successful treatment.
The RPS said: "We would be very concerned if a patient took a homeopathic preparation to travel to an area where there may be yellow fever, typhoid, malaria, believing they were safe when in fact they wouldn't be safe".
The second point the GPhC makes is that the allegation about Ainsworths "would fall below the current threshold criteria for referral to the investigating committee".
The test is now whether a pharmacist is being "reckless with the safety and wellbeing of others".
Ms Brown from Sense about Science says that if the regulator doesn't think "continuing to market useless homeopathic travel 'vaccinations' for diphtheria, malaria, polio, typhoid and encephalitis" and potentially putting lives at risk is not reckless then there's little point having regulation.
Former Liberal Democrat science spokesman Evan Harris, who is now the director of the Campaign for Evidence Based Policy, said that it was "hard to imagine cases where so many professional standards had been breached".
"If a doctor or a nurse had done this their respective professional bodies would have instigated a full investigation for professional misconduct," he told BBC News.
Dr Simon Singh, who writes critically of some so-called alternative medicine, said: "The evidence was served to the GPhC on a plate. I am shocked that as a regulatory body it would ignore its responsibility to protect patients."
The Nightingale Collaboration, which campaigns for evidence-based medicine, will submit a new complaint to the General Pharmaceutical Council on the basis of last week's Newsnight report.
Its director Alan Henness said: "This is a disgraceful state of affairs.
"Statutory regulation is there to protect the public. By taking so long to investigate and by dropping these complaints, the GPhC cannot be seen to be fulfilling this vital role."
The GPhC said that in the cases it investigated it did not consider that the individuals' fitness for registration was "impaired such that it ought to be removed or restricted".
"Although the cases are now closed," it told BBC News "the information gathered as part of the (recent Newsnight) investigation including the original complaint may be taken into account if we receive any further complaints about the pharmacy professional in the future."
BBC News contacted Ainsworths for a response. A spokesman said: "We do not make comments to the media."