Trimethoprim is an antibiotic medication primarily used to treat bacterial infections, particularly those affecting the urinary tract. It works by inhibiting the growth of bacteria, making it effective against a variety of infections caused by susceptible organisms. This medication is often prescribed alone or in combination with sulfamethoxazole, another antibiotic, to enhance its effectiveness. Common side effects may include nausea, vomiting, and skin rashes. It is important to take Trimethoprim as directed by a healthcare professional to ensure the best outcome and reduce the risk of antibiotic resistance.