McDonald's is to phase out the use of antibiotics that play a crucial role in human medicine on chicken sold at its UK outlets.
McDonald's Europe announced the plan to end use of antibiotics classified by the World Health Organisation as "highest priority critically important".
It said it would phase out the use of fluoroquinolones and marcolides over the next three years.
The move comes amid concerns that overuse of antibiotics in chicken and other animals may affect the medicines' effectiveness in humans.
The world's biggest restaurant chain earlier announced that it would stop US purchases of chicken injected with antibiotics important to human medicine.
A spokeswoman for McDonald's in the UK said: "In line with other retailers and the UK poultry industry, McDonald's UK and Europe continue to work closely with our suppliers to monitor and reduce the use of antibiotics among chickens in our supply chain.
"Alongside today's announcements from McDonald's USA, McDonald's Europe announced plans to phase out the use of those antibiotics that play a crucial role in the human treatment of specific and serious infections and diseases, from our poultry supply chain."
McDonald's Europe said in a statement: "McDonald's is committed to sourcing food from sustainable sources only using products and ingredients that meet high standards of quality and safety.
"Scientists and regulatory bodies worldwide are continuously reviewing how antibiotics are used in farming to address the concerns about increasing antibiotic resistance, while having proper regard for the welfare of farm animals.
"McDonald's is using its scale and influence to make an impact in the farming industry in global efforts to reduce antibiotic-resistant bacteria."
Marion Gross, senior vice president of the McDonald's North America supply chain, said that the company "believes that any animals that become ill deserve appropriate veterinary care and our suppliers will continue to treat poultry with prescribed antibiotics".
But after treatment the bird would "no longer be included in our food supply", she said.