Pesticides can be lethal to humans and one of the known pathways affected by pesticides is the acetylcholine pathway. Pesticides are highly lipo-soluble and are thus easily absorbed through the mucosa, respiratory system, skin and gastrointestinal tract. Since the Alto Douro Vinhateiro is a vineyard where the application of pesticides is performed with high intensity, it is of interest to study the effects of pesticides on the acetylcholine pathway in the winegrowers of this region. The study of the effects of pesticides on the activity of AChE contributed to the alert of the risks these products may cause and to the defense of security regulations in the agricultural activity, minimizing the dangers to which workers are exposed. Recognizing precociously this sort of incident, as well as a higher vigilance in health related to the usage of pesticides, are extremely relevant attitudes to diminish the number of cases and the severity of the intoxications.