Abstract: Faecal egg count was made in 80 schistosomiasis japomca patients with Kato-Katz quantitative smear method every two days, and daily output of eggs from feces were counted in 7 schistosome-infected dogs with the same technique.Variance analysis method was performed of log-transformed data. The results showed that there was statistically significant difference among the geometric means of EPG and EPD during 3 months in the same host.The egg output of adult S. japonicum in the feces was unstable in a certain period of time, but EPG and EPD appeared to fluctuate rhythmically every 4-6 days. For epi-demiological survey as well as for evaluation of the control effect, it is suggested that when faecal examinations are made with four smears every two days for 3-4 consecutive times, the average egg output may objectively reflect the intensity of infection.