Introduction and objective:
Sodium lauryl sulfate (SLS) is a widely used surfactant present in many personal care products. Despite its broad application, increasing evidence suggests potential cytotoxic and ecotoxic effects. The aim of the study is to evaluate SLS toxicity using in vivo, in vitro and microbiological models to assess risks to health and the environment.

Material and methods:
Toxic effects were assessed in zebrafish (Danio rerio) embryos (OECD 236) and mammalian cell lines: human fibroblasts (BJ) and rat cardiomyoblasts (H9C2). Cell viability was measured by MTT assay after exposure to SLS (1–200 µg/mL). Zebrafish embryos were observed for mortality, developmental changes and hatching rate after 96-hour exposure. Antimicrobial and antibiofilm activities were tested against Streptococcus mutans and Enterococcus faecalis using microdilution and biofilm assays.

Results:
SLS showed marked cytotoxic and cardiotoxic activity (LC₅₀: 38.46 µg/mL for BJ and 36.97 µg/mL for H9C2 cells). In zebrafish, developmental delay and morphological alterations occurred with LC₅₀ = 2.654 mM, indicating moderate acute toxicity. No significant changes in heart rate or locomotor activity were detected at sublethal doses. Antimicrobial effects were strain-dependent: S. mutans showed moderate sensitivity (MIC = 50 µg/mL), while E. faecalis remained resistant. Biofilm assays confirmed limited antibiofilm potential.

Conclusions:
SLS exhibits considerable cytotoxicity and moderate developmental toxicity, implying potential health and environmental risks. Limited antimicrobial and antibiofilm effects question its safety and efficacy in oral hygiene formulations, supporting the need for stricter evaluation of its use.