Cannabis is the most widely used drug in the world with a prevalence of 2.5%. France and Belgium are no exception. Moreover, pediatric cannabis intoxications are increasing due to the growing use of cannabis in the adult population. In this study, we seek to investigate whether there is a correlation between symptoms and biological data in order to facilitate the diagnosis of pediatric cannabis intoxication. Data were retrospectively collected from 11 French laboratories and 2 Belgian laboratories over 3-year period (2019–2021). This study involved 123 children aged 2 months to 4 years. There was a geographical gradient with an increase in intoxication cases from northern to southern regions. THC, 11-OH-THC and THC-COOH levels were respectively 24.4 ng/mL (range = 0.4–109 ng/mL; median = 17.3 ng/mL), 26.3 ng/mL (range = 0.6–263 ng/mL; median = 18 ng/mL) and 217 ng/mL (range = 0.6–921 ng/mL; median = 163 ng/mL). The most frequently observed symptom was drowsiness in 60.2% of cases. Coma (13.8%, n = 17), convulsions (4.1%, n = 5) and bradypnea (8.1%, n = 10) were the most severe symptoms. The increase of THC content in cannabis products could explain the increase in poisoning severity. However, according to the data collected, it does not seem that the clinical symptoms observed are correlated with plasma or blood THC concentrations. Indeed, cases of coma with Glasgow Coma Scale at 3 have been observed with plasma THC concentrations between 7 and 29 ng/mL.