We report on an infant who was admitted to hospital with severe neurological symptoms following passive inhalation of cannabis. To date, cannabis abuse has been described almost entirely in adolescents and adults. In early childhood, however, cannabis effects were almost exclusively discussed in the context of maternal prenatal exposure, and the direct exposure of infants to cannabis substances has been rarely discussed or taken into consideration in clinical assessment under daily settings. To the best of our knowledge this is the first case to report on cannabis toxicity in an infant after passive inhalation. This case report is aimed to draw attention to the differential diagnosis of cannabis toxicity in infants. Moreover, facing the increasing number of cannabis smokers such cases might be more prevalent and therefore physicians, health workers and parents should be alerted about the health hazards of cannabis substances abuse in the presence of children.