The effect of di/rhamnolipid on the viability of neonatal human keratinocytes grown in medium containing 10% fetal bovine serum. 500 keratinocytes were initially seeded with 1.5 × 105 3T3 mouse fibroblasts in 60mm tissue culture dishes. Starting from the first day in culture, cells were treated with 500μg/ml, 100μg/ml, 50μg/ml, 10μg/ml and 1 μg/ml concentrations of di-rhamnolipid BAC-3. After two week treatment cells were fixed with 10% formaline/PBS and stained with Rhodanile blue solution (1% Rhodamine, 0.5% NileBlue; Sigma-aldrich, St.Louis, MO, USA) and the dishes were scanned and the scanned images analyzed using program based on histogram values construed with Adobe Photoshop 4.0 software (Adobe System Incorporated, San Jose, CA, USA) to determine the area of the keratinocytes colonies.