Sulfamethoxazole and methicarbazone, should be sulfamethoxazole and methicarbazone, composed of a combination of preparations, the principle is that the combination of dual blockade of the metabolism of folic acid, the antibacterial effect is stronger than the single product, the strains of bacteria that are resistant to it less. Sulfamethoxazole and methotrexate form a compound preparation, namely, compound sulfamethoxazole tablets, the principle is that the combination of the two double blockade of bacterial folic acid metabolism, its synergistic antibacterial effect is stronger than that of a single product, and the number of strains of bacteria that are resistant to it is also reduced. Commonly used preparations include tablets, dispersible tablets, suspensions, granules, injections and eye drops. It is used for infections caused by sensitive bacteria, such as urinary tract infections, acute otitis media in children over 2 years of age, acute exacerbation of chronic bronchitis in adults, and Pneumocystis carinii pneumonia. Adverse reactions: common is allergic reaction, can be manifested as drug rash. Contraindications: contraindicated in pregnant women, lactating women, infants less than 2 months old. Precautions: Do not arbitrarily increase the dosage or prolong the duration of administration to avoid poisoning. This product, if necessary, should be used under the guidance of a physician, do not apply on your own.