The rising pollution of water bodies goes along with an increase of cyanobacteria in the micro biotic community. The ability of cyanobacteria to produce toxins is well known and many cases of poisoning of animals and humans have been described worldwide. Thereby the exposure routes are mainly via drinking water. Another possible risk is the irrigation of edible plants with cyanotoxin contaminated water, since plants are able to take up these toxins. This scenario is observed at the lake Chao (China). In this study the cyanotoxin content in vegetables (spring onion, pak choi and courgette) grown on the shore of lake Chao was investigated. This lake regularly exhibited massive cyanobacterial blooms (mainly Microcystis and Anabaena) for years. Most of the blooms exhibit two different cyanobacterial microcystins, microcystin-LR and –RR. The continuous irrigation of the plants with lake water led to high accumulations of microcystins in all vegetables. The microcystin concentrations in the vegetables were above the tolerable daily intake recommended by the World Health Organization.