Objective To investigate the influence of renal failure on the area under curve (AUC) and adverse reactions of docetaxel in breast cancer patients, and provide evidence for the dosage of docetaxel in renal failure patients. Methods A retrospective study was conducted on 24 patients with breast cancer who had undergone radical mastectomy and received AC-T adjuvant chemotherapy in our hospital from January 2019 to November 2021. According to renal function cases, the patients were divided into two groups: renal failure group (n=5) and normal renal function group (n=19). The clinical characteristics such as gender, age, body weight and body surface area of patients in two groups, docetaxel dose, blood concentration, area under the curve, liver and kidney function, white blood cell count and absolute value of neutrophil before chemotherapy were collected. Single factor linear regression was used to analyze the influencing factors of the AUC of docetaxel. Adverse reactions after chemotherapy with docetaxel including nausea and vomiting, bone marrow suppression, constipation and liver function injury were collected. CTCAE 4.0 evaluation standard was used to evaluate adverse reactions. Results The clinical characteristics of creatinine [908.0 (819.0, 1018.0) μmol/L vs 54.8 (52.0, 65.0) μmol/L] and creatinine clearance rate [4.9 (4.3, 5.4) ml /min vs 86.3 (59.3, 92.5) ml/min] of the renal failure group and the normal renal function group have significant difference (P<0.001), while no significant difference (P>0.05) were found in the body surface area [1.4 (1.4, 1.5) m² vs 1. 6 (1.5, 1.6) m²], docetaxel dose [70.4 (69.4, 73.0) mg/m² vs 74.4 (72.3, 91.2) mg/m²], body weight [(51.4±3.8) kg vs (51.5±5.5) kg]. Liver function, white blood cells and neutrophils were within the normal range before chemotherapy with docetaxel. There was no significant difference in AUC value [(1.6±0.6) mg·h/L vs (1.8±0.8) mg·h/L] between the two groups after chemotherapy with docetaxel (P>0.05). Linear univariate regression analysis indicated that the blood concentration at the end of docetaxel infusion was significantly associated with AUC of docetaxel (P<0.001), while the body surface area, dose of docetaxel, body weight, liver and kidney function were not correlated with AUC of docetaxel (P>0.05). After chemotherapy with docetaxel, adverse reactions of patients in the two groups: nausea and vomiting (grade I incidence: 40% vs. 57.9%, grade II incidence: 60% vs. 42.1%), myelosuppression (grade I incidence: 60% vs. 84.2%, grade II incidence: 20% vs 15.8%) and constipation (all mild constipation) had no significant difference (P>0.05). Conclusion Renal failure did not affect the exposure of docetaxel and the adverse reactions after chemotherapy with docetaxel in breast cancer patients.