Between 1954 and 1973, more than 2000 men entering military service as conscientious objectors participated in Project Whitecoat as medical research volunteers for the Army's biological warfare defense program. An assessment of self-reported, current health status among 358 "exposed" individuals and 164 unexposed control subjects found no conclusive evidence that receipt of investigational agents was related to adverse health outcomes. No differences in current overall health, current exercise levels, self-reported symptoms, and self-reported medical conditions were seen between the study groups. Possible associations were seen between exposure to antibiotics or other biological agents and self-reported asthma (13.0% vs. 2.4%, relative risk [RR] = 6.00, 95% confidence interval [CI] = 1.03-34.90, p = 0.050), as well as between receipt of tularemia vaccine(s) and self-reported asthma (13.3% vs. 2.4%, RR = 6.15, 95% CI = 1.03-36.70, p = 0.049) and increased frequency/severity of headaches (35.6% vs. 18.3%, RR = 2.46, 95% CI = 0.99-6.15, p = 0.074). However, the size of the population under study was insufficient to assert with confidence that these statistical associations are real.