Diffusion solid medium test was used to detect antibacterial activity in Physarella oblonga (Physaraceae) extracts obtained from plasmodial immobilization and in natura plasmodium. The extracts presented activity against Staphylococcus aureus (halos=14 mmf) and Mycobacterium smegmatis (halos=12 mmf e 13 mmf). Slower inhibition was obtained against Bacillus subtilis (halos=10 mmf e 9 mmf) and Pseudomonas aeruginosa (halos=10 mmf e 8 mmf). Escherichia coli presented resistence to all tested extracts. The chromatogram revealed likeness in the chemical composition of the extracts, explaining similarities in inhibitory potential. The substances with Rf 0,91 and 0,82, present in both extracts, could be inhibitor agents of bacterial growth.