Abstract: Growing in the liquid medium containing penicillin, the cells of the Cyanobacteria, Anabaena 7120, Nostoc flagelliforme, and Synechocystis 6803 were broken and vacuoles were released. Percentage of broken cells declined and percentage of broken cells increased with the growing days of the algae. The percentage of vacuoles to broken cells were respectively 0.7%, 0.8%, and 13.3% in the three types of algae Anabaena 7120, N.flagelliforme and Synechocystis 6803 which had grown for 3 days.