Trimethoprim hydrochloride is a bacteriostatic antibiotic and an orally active dihydrofolate reductase inhibitor. Trimethoprim hydrochloride is active against a wide range of Gram-positive and Gram-negative aerobic bacteria. Trimethoprim hydrochloride has the potential for the research of urinary tract infections, Shigellosis and Pneumocystis pneumonia. Trimethoprim hydrochloride can inhibit infection of Influenza A virus in chick embryo when combinated with zinc[1][2][3][4].