AIM: To study the biochemistry change in blood and the significance for forensic medicine to measure the consistency of K+ and Cl- in venous blood and analysis of the gases in blood by manual strangulation. METHODS: The rabbits were put to death by manual strangulation and the gases in blood and the consistency of K+ and Cl- in venous blood were measured respectively. RESULTS: The pH dropped (P < 0.005). The PCO2 was increased (P < 0.01). The PO2 decreased (P < 0.01). The O2SAT also reduced (P < 0.01). The HCO3- increased (P < 0.05), and so was the TCO2 (P < 0.05), the concentration of K+ rose remarkably (P < 0.01). The change of Cl- was not evident. CONCLUSION: The change on the biochemistry in blood for rabbits were obvious. There are significance for forensic medicine to measure the consistency of K+ and Cl- in venous blood and analysis of the gases in blood.