Amprolium (INN, trade names Amprovine, Amprolium, Amprol, Anticoccid) is a coccidiostat used in poultry. The drug is a thiamine analogue and blocks the thiamine transporter of Eimeria species. By blocking thiamine uptake it prevents carbohydrate synthesis. Despite only moderate efficacy it is well favoured due to few resistance issues and is commonly used in conjunction with sulfonamides prophylactically in chickens and cattle as a coccidiostat.