Surveys were performed to assess the acute health effects of aerial application of malathion bait over a large urban area. Three indirect attempts to assess utilization of health care services were made: (1) surveillance of a major hospital emergency department was undertaken, (2) ambulance dispatches were reviewed, and (3) emergency treatments for asthma at a university hospital were reviewed. These assessments were negative but insensitive. Prevalence of self-reported symptoms was assessed with two surveys that were subject to severe time constraints. Personal interviews of the same individuals, before and after the spraying, were conducted: one was conducted by telephone and the other by residential visit. Results indicated no detectable increase in acute morbidity. Also, after the spraying, there was a decrease in anxiety-related symptoms.