This study aims to determine the effect of ethanol tamarind leaves (Tamarindus indica L.) om histology and levels of the enzyme lactate dehydrogenase (LDH) in rat hearts induced by used cooking oil.This study used a completely randomized design with 25 male white rats devided into 5 groups: negetive control, positive control, 1, 2 and 3 doses treatment (150 mg/kg BW, 200 mg/kg BW, and 250 mg/kg BW), where each group consisted of 5 replications. The stages of this research were phytochemical screening, total flavonoid test, antioxidant test, oil quality test, measurement of lactate dehydrogenase (LDH) enzyme levels and cardiac histological observations. The data analysis used was one way ANOVA followed by Duncan’s test. The results showed that the dose of ethanol extract of tamarind leaves (Tamarindus indica L.) 250 mg/kg BW was the most optimal dose to reduce histological damage in the form of pycnotic percentage with an average of 30.40% and thickness of the myocardium of the heart with an average of 852.8 um and decreased cardiac lactate dehydrogenase (LDH) levels by an average of 152 U/L. The ethanol extract of tamarind leaves (Tamarindus indica L.) had an effect on the hearts of white rats (Rattus norvegicus L.) induced by used cooking oil.