Fifty-six children with either autism or pervasive developmental disorders not otherwise specified received one injection of secretin, a gastrointestinal hormone. Re-evaluation 3-6 weeks later found minimal but potentially significant improvements, including changes in gastrointestinal symptoms, expressive and/or receptive language function, and improved awareness and social interaction. A second double-blind study with 17 children found few clinically meaningful changes. (Contains references.) (Author/DB)