. >> reporter: child neurologist richard frye is looking for many treatments that can help children with an inexpensive generic drug derived from the vitamin folic acid that is currently described to ease side effects from cancer chemotherapy. >> it can really have a substantial impact on a very good percentage of children with autism. >> reporter: in some kids folic acid, essential for brain development can't get in. leucovorin bypasses that blockage and can help some autistic kids improve their ability to speak. blastoff he has a rocket ship. mason's first word came three days after he started taking leucovorin at the age of three. the baby was? >> purple. >> reporter: purple. currently doctors can only prescribe leucovorin for autism off label which means repurchasing a drug approved for one condition for another. >> we have done the science and the next step is we want to get more funding so we can actually get it fda approved. >> reporter: but there is one big problem. why haven't pharmaceutical companies invested in clinical trials to study leucovorin to treat autism? >> leucovorin