My mom always prepares salabat for us since we were kids when we have sore throat or cough which I adopted now that I'm a mother myself. To prepare it, thinly slice a ginger. Put the slices in a caserole with water and bring to a boil for a good 15mins or so. Best to squeeze in some calamansi or add a slice of lemon :) my kids, ages 2 and 4, drinks this too when they have coughs.
Here's what we usually do at home: Peel a thumb-sized ginger root, slice it thinly and put it in a pot with one cup of water. Bring it to boil. You may add calamansi and honey, which is perfect for sore throat and cough.