From time immemorial, people have used these natural herbs to make medicines by concluding traditional experience we can acknowledge the great value of these herbs in treatment of cough, flu, headache, constipation, back pain, arthritis, stomach pain, dyspepsia, flatulence... And gradually many medicines have appeared, handed down and commonly applied by people because natural medicines are often benign, non - toxic, safe, easy to use and not cause side effects.