Despite the prevalence of cannabis use in the community, reports of adverse effects in young children are rare. Two cases of cannabis-induced coma are reported following accidental ingestion of cannabis cookies. The possibility of cannabis ingestion should be considered in cases of unexplained coma in a previously well young child if signs of conjunctival hyperaemia, pupillary dilatation and tachycardia are present and other causes such as CNS infection or trauma are unlikely. Specific screening for cannabinoids should be undertaken.