Thiamphenicol and florfenicol are broad spectrum antibiotics closely related in structure and activity to chloramphenicol. Thiamphenicol and florfenicol have similar antibacterial spectra to chloramphenicol but have not been associated with aplastic anaemia (23). Both drugs have been used for the treatment of infectious diseases in cattle, pigs and poultry. Thiamphenicol and florfenicol are used extensively in veterinary medicine and their use in food producing animals could result in potentially harmful concentrations in tissue, organs and milk. The potential risk is reduced by withdrawal of the drug for a fixed period before slaughter, although residual levels may remain.