The Thais love their whiskey (laew), but the name whiskey also covers drinks that are made of mollasses (Rum).
Yaa Dong is the REAL Thai Whiskey! This is a Thai Herbal Whiskey. Though many Thai Whiskeys have something added this one is not only a recreational drink but directed as a cure for specific ailments. The law is hazy as to whether Yaa Dong is legal simply because it has mystery additives but usually a blind eye is turned to its public sale.
Lao Khao is distilled from rice beer (Sahtoe) and so is a true Thai Whiskey albeit clear & colourless and with a completely different taste to Scotch. It is sold like most alcohol in the local corner shop & usually in a brown bottle. You can be pretty sure that the Lao Khao bought there is reasonably safe. Not so with the home produced product which may have less than desirable effects.
It's not unusual today to see Lao Khao today with a snake or two or perhaps a scorpion pickled in the bottle along with a Ginseng root. Marketed with names like 'Cobra Whiskey' It is more of a product for the tourist market... something to take home with you.
Sang Som though commonly called 'Thai Whiskey' is not a whiskey at all but a rum. It has been distilled from sugar cane like all rums. Most all of 7/11's stock it & it would likely be the first bottle handed to you if you asked for Thai Whiskey.
Sangthip is yet another Rum but generally called a Whiskey. There are those who say it is just Sangsom with a different label on the bottle.
Mekhong could be considered something of a hybrid Whiskey/Rum. It has a mollasses & a rice source.