Theophylline is a drug, a phosphodiesterase (PDE) inhibitor, it is widely used in the treatment of respiratory diseases. It has a similar structure with caffeine and pharmacological properties. Theophylline can be found in the nature of black tea and green tea.
Theophylline is used to prevent and treat wheezing, shortness of breath, and chest tightness caused by asthma, chronic bronchitis, emphysema, and other lung diseases. It relaxes and opens air passages in the lungs, making it easier to breathe.