Exorphins from casein and gluten have been found by HPLC and mass spectroscopy with fragmentation pattern in quickly frozen urine. Removing the proteins that contain these peptides, by dietary intervention has been tried with behavioral effects. We wanted to know how fast such changes take place. Method: Parents and caregivers filled out ATEC scores (Autism treatment evaluation checklist) over time so that changes in scores could be registered. Results: In this group of children who all responded to diet the time required for a positive effect was months rather than weeks. Conclusion: Short term interventions are probably a waste of time and money, and at least 3 - 6 months trials seem to be necessary.