Qiu Sheng.
Height 186 cm, weight 70 kg, thick hair, ridiculously handsome.
USTC biology PhD, university scholarship recipient, basically the ultimate template every guy dreams of becoming.
But for all his apparent perfection, there's one hidden shame Qiu Sheng keeps to himself:
He has bad breath.
According to statistics from Uptodate—
The domestic incidence rate of halitosis is about 30%, meaning roughly one out of every three people suffers from bad breath.
Most of the time, it's just that we get used to our own stench after constantly smelling it, so we don't really notice anymore.
The causes of bad breath are actually pretty simple. In plain terms, there are two main culprits:
20% is due to Helicobacter pylori; 80% is the result of microbial metabolism in the mouth.
The latter includes a bunch of bacteria like Neisseria and anaerobic Streptococcus that I mentioned before.
In fact—
