Sulfonamides are broad-spectrum antimicrobial agents, inhibiting bacteria, toxoplasma and other protozoal agents such as coccidia. They interfere with the biosynthesis of folic acid in bacterial or protozoal cells by competitively preventing the incorporation of para-aminobenzoic acid (PABA) into the folic acid molecule, which is required for DNA and RNA synthesis in the pathogen. Pyrimethamine is an antiprotozoal diaminopyrimidine which inhibits at a later stage in the biosynthetic pathway of folic acid. Hence, the combination works synergistically by blocking different enzymatic steps in folic acid biosynthesis. Furaltadone is an antibacterial agent active mainly against Gram-negative bacteria such as Salmonella spp. Vitamin A is an essential nutrient involved in preservation and maintenance of healthy epithelial tissues and mucous membranes, and of a proper immune function. Vitamin K assists the animal in counteracting intestinal haemorrhages and lesions caused dirrectly by the pathogen or the parasite.