Tyfur w.s.p. (Tiamulin) is an advanced generation pleuromutilin derived semisynthetic broad spectrum bacteriostatic antibiotic which is highly active against Gram positive bacteria, some Gram negative bacteria and mycoplasma. Besides from prevention of bacterial diseases Tyfur w.s.p. has growth promoting effect, improves egg production & FCR in layers. and broilers semisynthetic derivative of pleuromutilin. Tiamulin is active against gram-positive bacteria, mycoplasmas, and anaerobes, including Brachyspira hyodyesntereiae. It is also clinically effective in treatment of swine dysentery and mycoplasma arthritis. Tiamulin is well absorbed when administered PO. The dosage is 8.8 mg/kg/day for 3–5 days, in either food or water. The parenteral dosage for mycoplasma pneumonia in pigs is 15 mg/kg. In poultry, tiamulin interferes with monensin and salinomycin metabolism, and if the drugs are fed together, they become toxic. Generally, however, tiamulin has few adverse effects.