Well he might have asked a 17 year old question, but he came here to ask the question just today and its still not answered correctly.
The tablets or powders must become wet. They can only be swallowed when wet , there’s plenty of saliva and stomach juices to make it wet… its never drying out. Its not going to create dust or “smoke”.
Its just fog, just as you get from your breath at some times on a cold day… We often breath out fog in cold air right ? Well the exact conditions can vary… It might not be so visible in freezing cold air, as that is perfectly dry… so it might be only visible on days when the air is very humid ( nearly 100% relative humidity ) , and above freezing.
And the normal breath might not create fog at the time , but the normal breath might be dry enough to hold the water vapor, at the resulting temperature …
The belch is gas from the top of the stomach, it could have been held there a while and at body temperature, so it could be filled with water vapor, and then its rapidly cooled down in the air outside, (which might also be humid cold air… )
The belch might even have occurred due to the taking of herbal medications on an empty stomach. Plants contain tannins - which are known stomach irritants - and a million other substances, some of which might irritate your stomach. Best not to take herbals for sore stomach, if its an ulcer, they may make the ulcer worse. And I doubt the herbals passed the tests as “better than a placebo” - which implies… placebo.
One treatment for sore stomach I found was fish oil tablets. Its very sticky and sticks to, adds to, the fatty lining of the stomach,and perhaps nourishing your body with the right oil needed to make more stomach lining… low fat diets could contribute to stomach pains like reflux, ulcer, irritation, belching … !..
Belching is a symptom of reflux or irritated stomach… your oesophagus and stomach are pulsing to try to clear the irritating substance away (whether its the acid or something you swallowed ) , and that pulsing pushes air in…
Its not plausible that the cigarette smoke was still existing as smoke in the air in the stomach after hours…