Inclusion Criteria for phase 1 study:  Pupils aged 3-15 years from Kindergarten to Secondary schools Agreement from parents with writen informed consent  Inclusion criteria for intervention:  Children infected with toxocariasis may have symptoms and the ELISA test is positive for Toxocariasis larvae, with or without increased BCAT and IgE.  ELISA results according to the specified Kit and read according to optical densities (OD).  Cases of suspected heart, lung, liver, eye damage ... referred to Children's Hospital 2 for examination by specialty and not for intervention.  Exclusion Criteria:  Children aged 3-15 years without writen informed consent from parents and themselves. Children infected with Toxocariasis larvae which are not common type. Children infected with Toxocariasis are suffering from acute diseases or other chronic diseases: Cardiovascular, hepatitis, kidney, stomach, mental, or suspected tumor... Children with a history of hypersensitivity to any ingredient in the treatment of Albendazole. Infected children do not have enough follow-up process before and after 1, 6 months of treatment.