OBJECTIVE： To observe the effects and safety of L-carnitine combined with antibiotics in the treatment of native valve endocarditis. METHODS： In retrospective study， a total of 100 patients with native valve infective endocarditis were randomly divided into control group and observation group with 50 cases in each group. Control group received corresponding symptomatic and supportive treatment， such as antibiotics， fluid infusion， lowering temperature； observation group was additionally given L-carnitine injection intravenously， 1 g each time， qd， on the basis of control group. The treatment course of 2 groups lasted for 4 weeks. Clinical efficacy， heart function index （LVEF， SV， CO， CI） and serum inflammatory medium （CRP， IL-6， IL-8， TNF-α） were observed in 2 groups， and the occurrence of complications was also observed. RESULTS： The total effective rate of observation group was 90.0％， which was significantly higher than control group （78.0％）， with statistical significance （P＜0.05）. The levels of LVEF， SV， CO and CI in 2 groups after treatment were significantly higher than before treatment， the observation group was significantly higher than the control group， with statistical significance （P＜0.05）； the levels of CRP， IL-6， IL-8 and TNF-α in 2 groups after treatment was significantly lower than before treatment， the observation group was significantly lower than the control group， with statistical significance （P＜0.05）. The incidence of complications in observation group （8.0％） was significantly lower than in control group（20.0％） during treatment， with statistical significance （P＜0.05）. CONCLUSIONS： L-carnitine combined antibiotics is better than antibiotics alone in the treatment of native valve endocarditis， can effectively control infection improve cardiac function， and significantly reduce the serum levels of inflammatory mediators and the incidence of complications.