Vegetable soups are considered to be good one. Specially when sprinkled with spices. Try to include ginger, black pepper and garlic into the diet. Cloves are considered to be one of the most excellent remedy. A glassful of lukewarm water with squeeze of lemon with ginger, black pepper and rock salt gives relief.
The latest research by Butler LM, Koh W-P, Lee H-P in the American Journal for Respiratory Critical Care Medicine reviles that dietary fiber may reduce the cough and phlegm associated with the respiratory diseases.
The patient should avoid meats, tea, coffee, sugar, pickles, refined and processed food, candies etc. as they may irritate the throat and produce cough.
In some area of India, it is tradition to have milk with 2-3 tbsp of turmeric powder. The paste of ginger, tulasi (holy Basel) and Liquorice definitely works. Try to avoid fruits like bananas, mangoes, dates which are heavy to digest. Spicy and oily food is strictly contraindicated. Give up cold beverages and junk food. Avoid anything that is not hot.