While there is continual awareness regarding exposure to mercury (Hg) sources in general and MeHg+ in particular due to its presence in food samples such as fish, less interest is paid to the potential risk from ethylmercury (EtHg+ or EtHgX). One of the main reasons for this is the faster degradation and consequently excretion of EtHg+ in the human body that results in considerably lower chronic toxicity. There remain however potential sources where acute intake of EtHg+ can occur, for example as a consequence of exposure to thiomersal. Thiomersal is used as a bactericide in multi-dose (typical concentration 0.001 to 0.01%)1 and in other health related products such as eye drops or contact lens solutions. The compound hydrolyzes in aqueous solution to form EtHg+ and thiosalycilate which is an effective bactericide. Although no direct correlation between thiomersal usage and potential health risks has been established2, the use of thiomersal has been reduced in both Germany and the USA. Its use is still permitted in multi dose vaccines and contact lens solutions at concentrations of up to 100 and 70 mg/kg respectively.