Turmeric and Black Pepper (often coupled with Ginger too) sounds like a bit of an unusual combination, but there's a good reason for this!
Ancient people were actually quite good at discovering that certain combinations of herbs worked better than by themselves, although I'm sure they didn't know why - and all without the help of modern science.
A great example of this would be the plant called 'Adhatoda', which actually translates to 'goat' and 'not touch' due to it being so bitter that even goats won't eat it. The fact that it tastes horrible makes it even more amazing that they were willing to experiment enough with it to make the discovery that it helps treat asthma!
When combined with Black Peppercorns, the Adhatoda plant dramatically increases its effectiveness.
Black Pepper contains Piperine, which reduces the livers ability to process certain compounds within the Adhatoda plant that are actually beneficial to those with Asthma. Our liver helps to remove things from our body by making them more water soluble - but black pepper helps to inhibit this process. Of course not long enough to be of any danger, yet long enough for the Ahhatoda compunds to enter the bloodsteam uninhibited and be of benefit to us.
The same method applies to Turmeric, which contains Curcumin.
If you take Turmeric normally, your Curcumin levels within the blood will go up a bit - but what happens if just a small amount of pepper is added?
Levels will rise by 2000% higher than without pepper.
Okay and finally - why would we want this to happen?
Studies have shown that Turmeric is known to fight inflammation, and therefore Arthritis and a range of other diseaese. Notice within this study that Ginger is also included - "Zingiber officinale (ginger), Boswellia serrata, Curcuma longa (turmeric)" which is one reason why Ginger is also added to this blend in many cases - apart from tasting great.
With the addition of Pepper to Tumeric, the benefits are greatly increased.