A model for predicting the uptake of tetracycline and amoxicillin by vegetable plants using STELLA (R) was developed. Simulations were performed for a 30-day period during which lettuce and carrot were irrigated with the two antibiotics of known concentrations. The model predicts antibiotic concentrations in several compartments, including porewater, soil, and plant tissues. Simulations showed that the number of antibiotics found in soil fraction was larger than the amount in plant tissues. The developed model for tetracycline uptake by carrot gave a chi-square (chi(2)) value of 0.2 and by lettuce recorded a chi(2) value of 0.6. The model was considered efficient based on the chi(2) values. Validation of the antibiotic's uptake model showed an appreciable agreement between simulated and measured experimental data with deviation expressed as percentage being 2.6% for tetracycline uptake by carrot model and 37.9% for tetracycline uptake by lettuce model. Leaching and evaporation processes of antibiotics were found from the sensitivity analysis of the model to be the most important processes influencing the uptake model. These processes could be determined accurately and hence makes the model easily adoptive for other antibiotics. Further antibiotic uptake studies should focus on the physical-chemical properties of the antibiotics and abiotic environmental condition effect on the uptake model developed.