This study investigates the hypothesis that metformin, an antidiabetic drug, reduces the risk of cancer in people with type 2 diabetes. Using record-linkage databases from Tayside, Scotland, the researchers identified new users of metformin between 1994 and 2003 and compared them with a matched group of diabetic patients who had never used metformin. The study found that cancer was diagnosed in 7.3% of metformin users compared to 11.6% of comparators, with a median time to cancer of 3.5 and 2.6 years, respectively (P < 0.001). The unadjusted hazard ratio for cancer was 0.46 (95% CI 0.40–0.53), and after adjusting for various baseline characteristics, the adjusted hazard ratio remained significantly reduced at 0.63 (95% CI 0.53–0.75). The results suggest that metformin use may be associated with a reduced risk of cancer, but a randomized trial is needed to confirm this finding. The study also highlights the importance of further research into the potential anticancer properties of metformin, which are likely mediated through the activation of AMP-activated protein kinase (AMPK).This study investigates the hypothesis that metformin, an antidiabetic drug, reduces the risk of cancer in people with type 2 diabetes. Using record-linkage databases from Tayside, Scotland, the researchers identified new users of metformin between 1994 and 2003 and compared them with a matched group of diabetic patients who had never used metformin. The study found that cancer was diagnosed in 7.3% of metformin users compared to 11.6% of comparators, with a median time to cancer of 3.5 and 2.6 years, respectively (P < 0.001). The unadjusted hazard ratio for cancer was 0.46 (95% CI 0.40–0.53), and after adjusting for various baseline characteristics, the adjusted hazard ratio remained significantly reduced at 0.63 (95% CI 0.53–0.75). The results suggest that metformin use may be associated with a reduced risk of cancer, but a randomized trial is needed to confirm this finding. The study also highlights the importance of further research into the potential anticancer properties of metformin, which are likely mediated through the activation of AMP-activated protein kinase (AMPK).