Trimethoprim is an antibiotic that is commonly used to treat bacterial infections. It works by inhibiting the production of a key enzyme in the folic acid pathway that is necessary for bacterial growth and replication. Trimethoprim is usually used in combination with other antibiotics, such as sulfamethoxazole, to increase its effectiveness against a wider range of bacteria. Trimethoprim is commonly used to treat urinary tract infections, respiratory infections, and other bacterial infections. It is available in various forms, including tablets, capsules, and oral suspension. As with all antibiotics, it is important to take trimethoprim as prescribed by your healthcare provider and to complete the full course of treatment to ensure that the infection is fully cleared.