More than 1.7 million blood glucose testing strips are being recalled over potential false readings.
The Medicines and Healthcare products Regulatory Agency (MHRA) said people with diabetes should not use the strips over fears they could give inaccurate results, leading to a patient injecting too much insulin.
The strips have been subject to a manufacturing fault. They are GlucoMen LX Sensor blood glucose test strips for use with the GlucoMen LX and GlucoMen LX PLUS blood glucose meter.
The strips are manufactured by Menarini in Italy and distributed in the UK. There are no reports at present of patients being harmed by using the strips, the MHRA said.
Just over 1.7 million test strips in the affected lots were sold to pharmacies in the UK between October and November 2012.
The affected lots are 3212219249 (expiry date 31/08/2014) and 3212214249 (expiry date 31/08/2014).
The MHRA is investigating why the manufacturer did not alert it to a potential problem with the strips until last month.
The strips were not distributed in the UK past November last year but officials are worried they may still be on shelves or people may still have them in their homes. The manufacturing fault has now been resolved.
John Wilkinson, the MHRA's director of medical devices, said: "People who have GlucoMen LX Sensor blood glucose test strips from these specific lots at home should not use them.
"The manufacturing fault in these test strips could give a misleading reading that may result in people overestimating the amount of insulin they need to take."