People who take medicine bought over the internet could be putting their health at risk, according to experts.
Many medicines can be bought over the internet
A survey of more than 100 pharmacy websites has found that few provide customers with adequate information to enable them to use the medicines safely and effectively.
Many also failed to inform customers of the potentially dangerous consequences of taking different types of drugs at the same time.
Researchers from Monash University in Victoria, Australia, surveyed 104 pharmacy websites from more than a dozen countries around the world, including the US, UK and Australia.
Two out of three were prepared to send medicines to customers living in other countries.
Lack of information
The researchers found that just two out of three websites provided information on the products they sold.
However, much of this information was poor and would not have enabled customers to make an informed decision on whether the drug would help them.
As part of the study, one of the researchers posed as a female customer from Australia who was already taking the antidepressant Prozac and wanted to buy the painkiller Sudafed or pseudoephedrine hydrochloride and St John's wort.
Pseudoephedrine hydrochloride is often used illegally to manufacture amphetamines. Some countries have strict controls on importing it.
We expect the same high standards of care from online pharmacies as we do from other pharmacies
Royal Pharmaceutical Society of Great Britain spokeswoman
People who take the herbal remedy St John's say it can help to fight depression. However, it can interact with many medicines including anti-depressant medication.
A total of 27 e-pharmacies supplied at least one of these products. However, almost half failed to provide information on how to use the drugs or their possible side-effects.
Just 11 websites sent information warning about the danger of mixing these drugs with other products.
Patients 'at risk'
The researchers concluded that the lack of information meant patients were being put at risk.
Writing in the journal Quality and Safety in Health Care, they said: "Consumers cannot make an informed decision about purchasing a medicine using information provided by e-pharmacies because balanced information about the benefits and risks of taking medicines was largely not available or of poor quality."
They added: "Surfing and self-medicating is currently not safe."
The Royal Pharmaceutical Society of Great Britain, which regulates pharmacists, said internet pharmacists are required to work in accordance with its code of ethics. This code states that the wellbeing and safety of patients must be their prime concern.
A spokeswoman said: "Pharmacists in Britain must comply not only with a Code of Ethics but also with the laws relating to medicines.
"All UK pharmacies, including on-line pharmacies, and pharmacists must be registered with the Royal Pharmaceutical Society of Great Britain.
"We expect the same high standards of care from online pharmacies as we do from other pharmacies."