<p>The use of anti-parasitic medicines in Veterinary is legally controlled in animal productions to avoid contaminations in meat products, milk, eggs, and honey, but there is no careful monitoring of the use of these medicines in pets. For this reason, the purpose of this article was to learn about the use of internal antiparasitic medications prescribed on small animals in veterinary practices, clinics, and hospitals in the city of Tunja, Colombia. For this purpose, a cross-sectional exploratory study was carried out in which the use of antiparasitic products in small animals was reviewed by Veterinary Doctors or Zootechnical Veterinary Doctors licensed in the city of Tunja. The data were analyzed in a descriptive way by means of proportions. It was found that 62.1% consider that parasitic infestation in dogs and cats is common. The protocols to control gastrointestinal parasites do not exceed three months and the most used product, although combined, is Prazicuantel. 70% of professionals consider that there is resistance of parasites to medications used as a prophylactic or therapeutic method. Therefore, antiparasitics is frequently used in the daily clinic of small animals and may favor the resistance of gastrointestinal parasites to these medicines, showing the need for more effective pharmacovigilance with the use of these medications.</p>