A young married man with a history of disturbed gastrointestinal functioning associated with fluctuation in his emotional state was the subject of an experiment. Urinary creatinine, 17-hydroxycorticoids, and uropepsin levels were determined daily as a means of measuring indirectly the degree of gastric activity. His psychoanalysis continued concurrently. Significant correlation was found between phases in the analytic process and certain relatively constant biochemical rhythms and balances. It was concluded that although the research helped to make some of the patient's regressive trends more amenable to analysis, the use of the patient for this research problem added difficulties to the analysis, particularly to the resolution of the transference.