Smilax myosotiflora A. DC., the horny little devil, is a tropical creeping plant which popularly consumed as a male aphrodisiac, energy booster and lumbago reliever in the old traditional medicinal. The scientific studies showed that the plant able to increase sexual behaviors and testosterone level in male rats. However, its toxicity effect is still remained unknown. Therefore, this study aimed to investigate the toxicity effects of S. myosotiflora methanol extract (SMME) through in vitro and in vivo studies. The SMME was subjected to the brine shrimp lethality test (BSLT) to determine the LC50. Acute and subacute toxicity studies according to the Limit Test of OECD guidelines no. 425 and 407 was carried out through oral gavage accordingly. It was found that the LC50 of SMME was 674.4ppm while its LD50 via acute test was more than 5000mg/kg. Neither sign of toxicity nor significant difference in food intake, weight gain, gross necropsy, the hematological and biochemical analyses and histological evaluations were recorded between the control and treated groups except for the level of AST and testosterone in male and sodium and triglycerides in female rats. The increase of testosterone in male might occur through specific pathway as the SMME did not increase the hormone level in the female. According to GHS classification, SMME in this study can be classified as Category 5 (Safe) and non-toxic. Data from this study can be served as a primary predictive guide for future research in assessing the efficiency and safety of S. myosotiflora consumption for human trial.