This paper provides an overview of the effects of transgenic plants, also known as Genetically Modified Organisms, and food safety. Modern biotechnologies are powerfull tools in reprogramming life. However, a major problem in the risk assessment of the organisms produced by biotechnology is that the outcome of transformations cannot be fully foreseen. Potential risks to human health include unpredicted side effects, allergy, toxicity and intolerance. The main effects on the environment include the gene lateral transfer, genetic pollution, and damage to non-target species. The substantial equivalence principle should be abandoned in favor of more scientific criteria. With the Biosafety Protocol approved January 2000, the precautionary principle was reaffirmed and the labeling became compulsory. The public perception reached a stage where restrictions on the consumption of genetically modified foods are imposed, compelling enterprises and scientists to a science-based approach for the risk assessment analysis.