Introduction: Cases of toxoplasmosis present in South America tend to be more severe than that found in other continents. Here, we present our clinical experience of ocular and ganglionar toxoplasmosis in the use of PCR, and of the treatment to prevent ocular involvement. Methodology: Retrospective analysis of clinical charts of patients with ocular and lymphadenitic toxoplasmosis at the parasitology and tropical medicine consultation in the “Universidad del Quindio” in Colombia. In total, 91 records of cases with ocular toxoplasmosis and 17 with lymphadenitis that underwent PCR analysis for B1 repeated sequence in blood, were compared to the results of 104 people with chronic asymptomatic toxoplasmosis. In addition, 41 clinical records were included from patients with confirmed toxoplasmic lymphadenitis: 10 untreated, 6 that begun treatment after four months of symptoms, and 25 that were treated during the first four months of symptoms and had a follow-up during at least one year. Results: Patients with ocular toxoplasmosis or lymphadenitis had a higher probability of PCR positivity in peripheral blood than chronic asymptomatic people. There were no cases of retinochoroiditis in 25 patients with toxoplasmic lymphadenitis treated before 4 months of symptoms and followed during at least 12 months. In four out of ten untreated cases, new lesions of retinochoroiditis presented after the symptoms of lymphadenitis. Conclusions: Toxoplasmosisin South America exhibits different clinical behavior and this influences the laboratory results as well as the need for treatment in the case of lymphadenitis. Clinicians should be aware of the geographical origin of the infection in order to adopt different therapeutic and diagnostic approaches. © 2018 Elsevier B.V.