Isotretinoin has been used to treat severe inflammatory acne that is resistant to antibiotics or topical agents; however, it also may cause alterations in lipids and liver enzymes. In this retrospective study, we evaluated changes in lipids and liver enzymes in 322 acne patients who had been treated with oral isotretinoin at our institution over a 3-year period. Each patient's medical records were evaluated to determine baseline triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels compared to levels recorded at 3 and 6 months following initiation of treatment with oral isotretinoin. Overall, statistically significant increases in TG and LDL levels were noted following treatment with isotretinoin (P<.001, respectively), while HDL levels were shown to decrease (P=.016). Although ALT levels also increased, the changes were not statistically significant increases in AST levels also were noted (P=.72). In our study, isotretinoin appeared to have a greater effect on lipids than liver enzymes. Dermatologists should not avoid isotretinoin use for appropriate indications, but close follow-up is important.