Stay away from Drugs!
BackThailand's drug laws are very strict, except for marijuana, of course, which is now legal, albeit with some restrictions on public use and age limit.
You are not permitted to use cannabis in public, only in the privacy of your own home. Most hotels and apartment will not permit the use of cannabis on their premises.
Narcotic & psychotropic drugs, however, are still very much illegal.
Class A drugs like heroin, cocaine, LSD, or Ketamine will land you in the slammer for a considerable amount of time.
Get caught with a substantial amount and your only hope is a pardon from the King, sometime in the next 60 years.
Prescription drugs are heavily regulated too. Some require a permit, and the majority are restricted to 30-days’ worth – in the original packaging and accompanied by the prescription.
And finally, Vaping is totally illegal anywhere.