Abstract: Objective To investigate the safety and maximum tolerable dosage of injectable cefetamet sodium with a single infusion in Chinese healthy volunteers. Methods Sixty healthy volunteers were enrolled in this study. A double-blinded, randomized, placebo-controlled design was adopted. Eight dosages ranging from 100 mg to 5 000 mg were tested. The pharmacokinetics of the drug was analyzed using a Latin square three-cross self-controlled design, with 12 healthy volunteers receiving 500 mg, 1 000 mg and 2 000 mg of injectable cefetamet sodium in a randomized sequence. Blood and urine samples were collected and analyzed using high performance liquid chromatography with UV detection. The main pharmacokinetics parameters were calculated with DAS2.0 software. Results 59 healthy volunteers completed the tolerance tests. Clinical adverse reactions occurred in 22.73% of participants in the test group and 6.67% of participants in the placebo group; but the difference was not statistically significant. Common adverse events included infusion pain and dizziness. Rare adverse events such as palpitations, diarrhea and rash occurred in participants in the test group. All of the adverse reactions were mild. Abnormal laboratory test results occurred in 43.18% participants in the test group and 53.33% participants in the placebo group; again the difference was not statistically significant. Common abnormal laboratory test results included abnormal bowel flora, stool abnormalities, abnormal urine and elevated serum potassium. After a single infusion of 500 mg, 1 000 mg and 2 000 mg of injectable cefetamet sodium, peak concentration of the drug at 0.5 h reached (37.92±7.43), (74.90±10.67) and (148.54±31.63) mg/L, with areas under concentration-time curve of (72.08±14.98), (144.28±24.57) and (286.66±54.25) (mg·h)/L, respectively. Their elimination half-life was (2.03±0.38), (2.04±0.26), and (2.12±0.26) h, respectively. The disposition of cefetamet was presented as a two-compartment model with linear kinetics. The 24-hour urinary accumulation excretion was 76.6%-67.5%. Conclusion The maximum single tolerated dose of injectable cefetamet sodium is 5 000 mg. The pharmacokinetics is a two-compartment model with linear kinetics within a dose range 500-2 000 mg.