Children with Autism spectrum disorders (ASDs) appear to be at risk for Zn deficiency, Cu toxicity, have often low Zn/Cu ratio, and often disturbed metallothionein (MT) system functioning. The evidence presented in this paper suggests that providing Zn to autistic children may be an important component of a treatment protocol, especially in children with Zn deficiency. It is important to monitor and follow the values for both Cu and Zn together during Zn therapy, because these two trace elements are both antagonists in function, and essential for living cells.