Tiamulin is a carbotricyclic compound that is pleuromutilin in which the hydroxyacetate group is replaced by a 2-{[2-(diethylamino)ethyl]sulfanyl}acetate group. An antibacterial drug, tiamulin is used in veterinary medicine (generally as its hydrogen fumarate salt) for the treatment of swine dysentery caused by Serpulina hyodysenteriae. It has a role as an antibacterial drug. It is an organic sulfide, a carboxylic ester, a secondary alcohol, a carbotricyclic compound, a cyclic ketone, a tertiary amino compound, a tetracyclic diterpenoid and a semisynthetic derivative. It is functionally related to a Pleuromutilin.