Synthroid is a sulfonamide antibacterial drug, which is an antibiotic with a wide antibacterial range, that is, an anti-inflammatory drug. It is commonly used clinically for the treatment of bacterial infections such as E. coli, H. influenzae and Streptococcus pneumoniae, the emergence of urinary tract infections, bronchitis, otitis media and the prevention of epidemic meningoencephalomyelitis caused by meningococcus. The more common adverse reactions are drug rash allergy, serious can cause exfoliative dermatitis, maculopapular epidermolysis bullosa atrophica dermatitis, etc. Anaphylaxis is relatively rare. Sulfasalazine allergic patients, pregnant women and lactating women are prohibited Synthroid, if found to have liver and kidney insufficiency should also be cautious use of this product. Because the drug has more adverse reactions, coupled with many common clinical pathogens currently resistant to Synthroid, so the clinical use is relatively small.