People with conditions such as HIV, TB and malaria should not rely on homeopathic treatments, the World Health Organization has warned.
It was responding to calls from young researchers who fear the promotion of homeopathy in the developing world could put people's lives at risk.
The group Voice of Young Science Network has written to health ministers to set out the WHO view.
However practitioners said there were areas where homeopathy could help.
In a letter to the WHO in June, the medics from the UK and Africa said: "We are calling on the WHO to condemn the promotion of homeopathy for treating TB, infant diarrhoea, influenza, malaria and HIV.
"Homeopathy does not protect people from, or treat, these diseases.
"Those of us working with the most rural and impoverished people of the world already struggle to deliver the medical help that is needed.
"When homeopathy stands in place of effective treatment, lives are lost."
Dr Robert Hagan is a researcher in biomolecular science at the University of St Andrews and a member of Voice of Young Science Network, which is part of the charity Sense About Science campaigning for "evidence-based" care.
He said: "We need governments around the world to recognise the dangers of promoting homeopathy for life-threatening illnesses.
"We hope that by raising awareness of the WHO's position on homeopathy we will be supporting those people who are taking a stand against these potentially disastrous practices."
Dr Mario Raviglione, director of the Stop TB department at the WHO, said: "Our evidence-based WHO TB treatment/management guidelines, as well as the International Standards of Tuberculosis Care do not recommend use of homeopathy."
The doctors had also complained that homeopathy was being promoted as a treatment for diarrhoea in children.
But a spokesman for the WHO department of child and adolescent health and development said: "We have found no evidence to date that homeopathy would bring any benefit.
"Homeopathy does not focus on the treatment and prevention of dehydration - in total contradiction with the scientific basis and our recommendations for the management of diarrhoea."
Dr Nick Beeching, a specialist in infectious diseases at the Royal Liverpool University Hospital, said: "Infections such as malaria, HIV and tuberculosis all have a high mortality rate but can usually be controlled or cured by a variety of proven treatments, for which there is ample experience and scientific trial data.
"There is no objective evidence that homeopathy has any effect on these infections, and I think it is irresponsible for a healthcare worker to promote the use of homeopathy in place of proven treatment for any life-threatening illness."
However Paula Ross, chief executive of the Society of Homeopaths, said it was right to raise concerns about promotion of homeopathy as a cure for TB, malaria or HIV and Aids.
But she added: "This is just another poorly wrapped attempt to discredit homeopathy by Sense About Science.
"The irony is that in their efforts to promote evidence in medicine, they have failed to do their own homework.
"There is a strong and growing evidence base for homeopathy and most notably, this also includes childhood diarrhoea."
The UK's Faculty of Homeopathy added that there was also evidence homeopathy could help people with seasonal flu.
Dr Sara Eames, president of the faculty, said people should not be deprived of effective conventional medicines for serious disease.
But she added: "Millions die each year as those affected have no access to these drugs.
"It therefore seems reasonable to consider what beneficial role homeopathy could play. What is needed is further research and investment into homeopathy."