A pharmaceutical formulation for oral administration containing root, bark and wood of Philippine Narra tree (Pterocarpus Indicus) in dried powder form in sachet in a unit of (2) to (3) grams and made into a decoction of (8) ounces or in capsule in a unit of (100) to (300) milligrams at a dosage of three to six times a day can enhance the immune system of a person and can be used for the prevention and treatment of ASTHMA.