Tested bacteria Mean zone of inhibition (mm) ± SD
Ginger Black cumin Thyme Clove peppermint
Gram-negative:  
E. coli

Pseudomonas aeruginosa
15.00 ± .78a
4.00 ± 0.18c
2.00 ± 0.14d
9.60 ± 0.15a
8.00 ± .14b
9.00 ± .12a

2.00 ± 0.12d
6.60 ± 0.12b

5.00 ± .19c
4.00 ±0.15c
Gram-postive:
Bacillus cereus

Lactococcus lactis

Listeria monocytogens
Staphylococcus aureus
11.60 ± 0.43a
11.00 ± 0.22c
9.00 ± 0.18b
5.70 ± 0.20c
5.00 ± 0.14e
22.30 ± 0.50a
9.50 ± 0.22a
9.00 ± 0.17a
8.30 ±0.22c
7.30 ± .15d
9.00 ±0.23b
0.00 ± 0.0d
9.30 ± 0.22b
7.60 ± 0.19d
8.30 ± 0.21c
0.00 ± 0.0d
7.00 ± .10d
16.00 ± 28b
6.30 ± .18d
6.33 ±0.15b
a,b,c,d means in the same row with different superscript differ significantly (p<0.05)
Table 1: Antibacterial activities of infusion of medicinal plants.