A UN drugs agency warned Thursday against underestimating the dangers of cannabis.
"The international community may wish to review the issue of cannabis," the International Narcotics Control Board (INCB) wrote in its annual report.
"Over the years, cannabis has become more potent and is associated with an increasing number of emergency room admissions," the report stated.
Cannabis was often the first illicit drug taken by young people and was frequently called a "gateway drug," in that it could lead to later use of hard drugs.
"In spite of all these facts, the use of cannabis is often trivialised and, in some countries, controls over the cultivation, possession and use of cannabis are less strict than for other drugs," the INCB said.
Indeed, many countries allowed the "recreational" use of cannabis, and public perceptions of the so-called "medical" uses of the drug and its recreational use "are overlapping and confusing," it said.
The agency also expressed "alarm" at the development of "rogue" or illegal Internet pharmacies.
The agency said it had long been concerned about the role of the Internet in the sale and distribution of controlled and uncontrolled substances and was aware of numerous cases involving illegal Internet pharmacies.
While it recognised "that purchasing pharmaceuticals online can be beneficial, especially in areas where hospitals and pharmaceutical services are widely dispersed, (the INCB) is alarmed that 'rogue' pharmacies are encouraging drug abuse among vulnerable groups."
The report called for international action "to address the illegal sale of drugs on Internet pharmacies and websites."
It also urged governments to "stimulate" the controlled use of opiate-based painkillers to help "alleviate unnecessary suffering of millions of patients."
"Although the access to controlled medicines, including morphine and codeine, is considered by the World Health Organisation (WHO) to be a human right, it is virtually non existent in over 150 countries," the report said.
"The WHO estimates that at least 30 million patients and possibly as many as 86 million annually suffer from untreated moderate to severe pain."
The report also highlighted a big increase in drugs being trafficked through eastern Europe.
"The smuggling of cocaine through Eastern European countries has significantly increased in the past few years," it said.
Western Africa had also become a "major hub" for cocaine smugglers on the route from South America to Europe, the INCB added.
According to the study, some 27 percent, or 40 tons, of the cocaine consumed every year in Europe transited through western Africa.
This was due to its geographic location but also to "weak governmental structures that have limited capacity to defend themselves against drug trafficking and its consequences, such as corruption and drug abuse," it added.