<p>Cotrimoxazole having broad spectrum bactericidal activity against a wide range of gram-positive &amp; gram-negative bacteria and some protozoa. Co-trimoxazole containing Trimethoprim and Sulphamethoxazole in a 1:5 combination exerts its bactericidal action by the sequential blockade of two bacterial enzyme systems in the biosynthesis of folinic acid in the microorganism.</p>