A Budesonide + Formoterol inhaler is generally safe and commonly used for long-term control of asthma and COPD when taken as prescribed. It contains a steroid (budesonide) to reduce airway inflammation and a long-acting bronchodilator (formoterol) to keep the airways open, helping prevent symptoms like wheezing and breathlessness. Most people tolerate it well, but some may experience mild side effects such as throat irritation, hoarseness, or oral fungal infection (thrush), which can be reduced by rinsing the mouth after each use. Serious long-term side effects are uncommon at recommended doses when used under medical supervision. It is important to use the inhaler regularly as advised and not stop it suddenly without consulting your doctor.