Advair and Symbicort both contain an inhaled corticosteroid and a long-acting beta agonist (LABA). However, Seretide contains fluticasone and salmeterol while Symbicort contains budesonide and formoterol. The best medication is the one that works for you depending on factors such as cost, potential side effects, and response to treatment. Consult a healthcare provider on the best treatment for you.