More than 30% of random samples of cannabis-based beverages contain amounts of Tetrahydrocannabinol (THC), cannabis' psychoactive ingredient, in excess of the legal limit, according to research from Chulalongkorn University.
Assoc Prof Kuakarun Krusong, a lecturer of biochemistry at the university's faculty of science, conducted a study which found that about 30% of randomly chosen samples contained more than the 0.015 milligrammes per 100 millilitres of drink limit set by the Public Health Ministry.
So far, the authorities have not given any recommendation on how much of the substance can safely be consumed per day or what adverse effects of doing so may follow, she said, adding that long-term studies on the effect of cannabis consumption have yet to be completed.
"Vendors do not know the THC limit per serving. Even those that do cannot control the amount precisely. The process also varies from one vendor to another," Assoc Prof Kuakarun said.
Meanwhile, Dr Prasit Watanapa, dean of the Faculty of Medicine Siriraj Hospital, Mahidol University, banned use of cannabis in foodstuffs and drinks on the university's premises.
The use of cannabis and hemp as an ingredient is forbidden, as is the advertising of cannabis-based products, an announcement said.
Also, those who receive services at the university, including staff and students, are not allowed to use cannabis recreationally.
The university supports the use of cannabis in accordance with recommendations from medical professionals, and anyone below the age of 20 and pregnant women are advised to avoid its use given the potentially harmful effects on health, it said.
The BMA recently declared all city-run schools under its jurisdiction as cannabis-free zones.
The de-listing of hemp and cannabis from the government's list of Category 5 narcotics took effect on June 9 following the publication of a Ministry of Public Health announcement in the Royal Gazette.
Consequently, the production, import, export, distribution, consumption and possession of cannabis and hemp are now legal.
However, cannabis oil extracts containing more than 0.2% THC are still considered a Category 5 substance, and regulated by the kingdom's narcotics control and suppression laws.