Tong Sum with black and red dates to cure dry cough

I have been having dry cough for almost 2 weeks now. The "dry" I mean is those cough without phlegm and I can feel my lung is sort of breathing heavily at one time and breathless at the other.

This is what recommended by the Chinese medicine shop.

10 Tong Sum (Codnopsis Pilosulae Radix)
1 handful of black dates
1 handful of red dates

1) Cut the Tong Sum sticks into small pieces.
2) Remove the seeds from black and red dates.
3) Add in water to the brim of the pot.
4) Put to slow cooker for 4 hours or boil for at least 1 hour and 30 minutes.

NOTE: My cough has reduced. Another good thing is that, my son's diarrhoea has stopped after drinking this!