A drug surveillance study has been carried out with oral cytidine diphosphate choline (CDP-choline, citicoline, Somazina) in 2817 patients of all ages, predominating those between 60 and 80 years old. They were suffering from several neurological processes, mainly the vasculocerebral insufficiency and senile involution. Treatment was carried out for between 15 days and 2 months, the mean dose being 6 ml/d. The efficacy of the treatment was determined on the basis of the disappearance, improvement or worsening of clinical manifestations, most frequently shown by patients. The most benefited clinical manifestations by the treatment were: dizziness disappearing in 48.4% of the cases, and improving in 25.2%, cephalea disappearing in 46.5% and improving in 26.7%, insomnia with 38.6% and 24.9%, respectively; depression with 36.9% and 24.1% and memory shortage with 21.2% and 44.7% respectively. The best results were obtained in chronic cerebrovascular insufficiency, the improvements obtained in dizziness, cephalea, insomnia, fatigue and speech troubles being the most important. The safety of the drug was excellent since side effects were observed only in 5.01% of the patients. Among these effects, the most frequently seen were digestive troubles, observed in 3.6% of the cases.