As more places legalise marijuana , scientists are warning of the potential health risks of eating cannabis-infused snacks . With smoking , the peak blood levels happen within 3-10 minutes , and with eating , it 's 1-3 hours , making it easier to overdose on food-related cannabis products . Now experts are warning that legalised marijuana needs to have strong restrictions on the drug 's edible products , which are often packaged to appeal to children . Scroll down for video . As more places legalise marijuana , scientists are warning of the potential health risks of eating cannabis-infused snacks.With smoking , the peak blood levels happen within 3-10 minutes , and with eating , it 's 1-3 hours , making it easier to overdose on food-related cannabis products . The problem is that marijuana edibles – which often look like candy or cookies and are frequently potent – increase the chances that children will overdose , they say . 'As legalisation of marijuana spreads , new adopters should ensure that their regulatory scheme for marijuana edibles is fully baked , ' wrote Robert MacCoun and Michelle Mello of Stanford Law School . Marijuana use for adults over 21 is fully legal in Colorado , Washington and Alaska . Oregon passed a similar law that will take effect in July . Several other states have legalised marijuana for medicinal use or have decriminalised it . A notable feature of state-legalised retail sales of marijuana has been the popularity of edibles . The problem is that marijuana edibles – which often look like candy or cookies and are frequently potent – increase the chances that children will overdose , they say . ' As legalisation of marijuana spreads , new adopters should ensure that their regulatory scheme for marijuana edibles is fully baked , ' the Stanford experts warned . Professor MacCoun explained that the original marijuana laws 'were not rigorous and detailed in their approach to issues like edibles , . Colorado and Washington put extremely modest rules on edibles , therefore making it easy to sell and market edible products , he said . 'Both states require child-resistant packaging , a warning to 'keep out of the reach of children , ' and labelling describing a standard serving size , ' wrote MacCoun and Mello . 'Neither requires warnings that ingested marijuana can have different effects from smoked marijuana . ' Some of the edibles look like Hershey or KitKat bars , and the drinks resemble the major brands of non-marijuana colas . Motor neurons ( pictured ) are nerve cells found in the cerebral cortex of the brain stem , and are responsible for giving orders to muscles . Marijuana users can sometimes have difficulty speaking , breathing and swallowing food as a result of muscle weakness . Now researchers in Spain have conducted a landmark study to shed light on how marijuana reduces the activity of motor neurons that lead to these symptoms . Motor neurons are nerve cells found in the cerebral cortex of the brain stem , and are responsible for giving orders to muscles in the body . Researchers at the University of Cadiz , led by Professor Bernardo Moreno , used synthetic analogues of the psychoactive compounds of marijuana to see how they affected these neurons . They looked , in particular , at movements of the tongue and how they responded to the drug . 'During the investigation , we used an animal model in which we studied the alterations produced by synthetic cannabinoids on the activity of the motor neurons , ' the researchers wrote . 'In doing so , we discovered that these psychoactive compounds inhibit the information that reaches these neurons via the synapses . 'In other words , cannabinoids hinder the transmission of information between neurons . ' All of this could lead to problems speaking , breathing and swallowing food . 'It evokes tobacco companies ' use of advertising campaigns with youth appeal , ' MacCoun and Mello wrote . They acknowledge that marijuana is associated with a long history of 'public misinformation ' about the effects of the drug . But the scientific record is clear on the documented risk of edibles , especially for children . 'Some of these products contain four or more times the level of tetrahydrocannabinol ( THC ) that is considered to be a safe dose , ' they noted . Taken in large doses , THC can produce serious anxiety attacks and psychotic-like symptoms , according to MacCoun and Mello . And strong differences exist in the effects of marijuana when it is eaten rather than smoked . Case reports document respiratory insufficiency in young children who have ingested marijuana through edibles , MacCoun said . A recent study showed that the proportion of ingestion-related emergency department visits by children in Colorado associated with marijuana ingestion increased after legal restrictions were eased . The majority of identified sources in those cases were marijuana edibles .
It takes longer feel impact of eating marijuana compared with smoking . Stanford researchers warn that this can cause people to eat too much . Marijuana use for over 21s is legal in Colorado , Washington and Alaska . Comment: but experts say this is not enough . Some of the edibles look like Hershey or KitKat bars , and the drinks resemble the major brands of non-marijuana colas , putting children at risk .