In his study of the diagnostic aspects of patients with failure to thrive (see p 967 in this issue), Sills points out that only 1.4% of the laboratory studies performed were of positive diagnostic assistance. He found that none of the laboratory studies was of value without a specific clinical indication. This has been suspected by others from anecdotal data.1 Another important aspect of the investigation by Sills was the finding that half of the children who were being evaluated because of failure to thrive were found to be suffering from environmental deprivation and that this syndrome was the most common cause of failure to thrive in the series reported. The author noted that previous workers have reported higher frequencies of the diagnosis of organic disease, and he attributed this anomaly to a tendency to undervalue the psychosocial investigation of the affected family. This has also been my experience,