Cytochrome P450 enzymes (P450s) play a critical role in drug metabolism, with the CYP3A subfamily being responsible for the biotransformation of over 50% of marked drugs. While CYP3A enzymes are known for their extensive catalytic versatility, one intriguing and less understood function is the ability to mediate carbon-carbon (C-C) bond cleavage. These uncommon reactions can lead to unusual metabolites and potentially influence drug safety and efficacy. This review focuses on examining examples of C-C bond cleavage catalyzed by CYP3A, exploring the mechanisms, physiological significance, and implications for drug metabolism. Additionally, examples of CYP3A-mediated ring expansion via C-C bond cleavages are included in this review. This work will enhance our understanding of CYP3A-catalyzed C-C bond cleavages and their mechanisms by carefully examining and analyzing these case studies. It may also guide future research in drug metabolism and drug design, improving drug safety and efficacy in clinical practice.