A worrying 62 per cent of medicines purchased online are fake or substandard, according to an industry campaign group.
The European Alliance for Access to Safe Medicines (EAASM) said that medicines researched by the organisation included drugs to treat serious conditions such as cardiovascular and respiratory disease and neurological disorders.
The EAASM warned that the rapid growth of illegal online pharmacies creates a much higher risk that fake medicines will reach patients.
Unsuspecting consumers are extremely vulnerable to the potentially lethal outcomes of buying medicines online, the report says.
The EAASM ordered common prescription-only medicines from over 100 online pharmacies. All medicines were delivered without requiring a prescription, which is illegal and presents a serious threat to public health.
The research suggests that 95.6 per cent of online pharmacies are operating illegally, and 94 per cent do not have a verifiable pharmacist.
Some 90 per cent supply prescription-only medicines without a prescription, and online 'pharmacy approval' stamps were found to be fake in 86 per cent of purchases.
The report demonstrates that there is a three in five chance of receiving a fake or substandard medicine when buying online.
Only 38 per cent of the medicines received by the EAASM were found to be genuine branded medicines.
Around 16 per cent were illegal non-EU imports, and 33 per cent did not have information leaflets which is also illegal and potentially dangerous to health.
Shockingly, on a number of occasions, the life-saving cardiovascular medicine Plavix was supplied with free 'Viagra'.
Anyone taking medicines for a serious heart condition should be under close medical supervision, especially when taking a cocktail of drugs for other conditions, including erectile dysfunction.
Ian Banks, president of the European Men's Health Forum, said: "I was al armed to see that a number of the 'medicines' delivered were accompanied by free, unsolicited tablets provided without any medical assessment.
"Far from rewarding consumers with 'bonus pills' this practice shows that these unscrupulous, criminal online drug traders appear willing to risk the health and well-being of their 'customers'."
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