Hi PennyPru,
You would need to check that each herb you plan to take has a safe interaction (or no interaction) with each other individual herb and drug you are taking. Lots of herbs and drugs are bad to be taken together - the best known example is that many herbal treatments prevent oral contraceptives from working. But, there can be far worse consequences that this, for example some herbs can cause liver problems, which would be made worse if you are already on antibiotics. You would be best to check with an expert. Spacing out the drugs and herbs won't necessarily be enough.
Might be worth starting by checking the leaflet than comes with your antibiotics. There can be some really odd things you need to avoid e.g. with Doxy you shouldn't take grapefruit. The problem is that few herbal remedies have been studied in the same detail as pharmaceuticals (St Johns Wort is one of the few that has been rigirously assessed), and so people don't necessarily know what they can clash with. The other problem is that certain chemicals can effectively neutralise each other. So, if you take the wrong herbal treatments your antibiotics will stop being effective. More drugs/herbs is not necessarily better than less...
I would suggest you stick to well established herbal treatments if you do go down this path, and make sure you see an expert.
Good luck,
Kirsty