The import, consumption, production and possession of drugs (cannabis, hashish, marijuana, heroine, cocaine, etc.) is forbidden and severely punished even if small amounts are involved. 

Anyone who needs to take medicines which contain the above-mentioned substances has to carry a medical certificate which justify that their import in the UAE is for therapeutic reasons and that their quantities are proportioned to the prescription. These regulations are strictly applied when transiting through the Country too.
The legal provisions for consumption and possession of drugs is strictly applied, regardless of the quantity held. They consist in the detention from four to ten years, up to a maximum of fifteen years (in case of aggravating circumstances and recidivism) and, in the worst case, the capital punishment (due to drugs trafficking). Anyone who gets information about these kinds of crimes and doesn’t go through the right Authorities could be charged with complicity. The civic-minded would be furthered with a 200.000 Dirhams premium (about 40.000 Euros)