Barhang is mostly known as its special effect on digestive system. Usually excess coldness can lead into poor digestive system. Gas issue, reflux, acidity, vomiting during pregnancy, it being able to digest the food properly, etc all are due to coldness of tummy and the Holy Prophet said: the tummy is the house of diseases.
So in order to warm up our digestive system there are different methods: First is to stop drinking cold water or juice or sodas while eating foods. Second is to start and end our foods with a pinch of sea salt. Third is to avoid drinking excess water and black tea.
One tablespoon of Broad leaf plantain seeds (Barhang) and one tea spoon of dry or fresh mint should be boiled in 2 cups of water and then mix it with some honey and drink it every night before sleeping.
Kahkashir seeds as well can be beneficial in adjusting digestive system.