Hi,
We seem to be talking about a number of different illnesses here. Sepsis is basically an infected wound, and can be associated with a number of different bacteria. Traditional methods for dealing with such things often involved debriding of the wound (cutting out the dead parts), various poultices and herbs applied topically, and others ingested to reduce the fever. Honey actually has quite a reasonable antibacterial effect when applied topically though it won't compare to a modern antibacterial creme, and maggots are quite effective at debriding dead flesh. They're being trialed at present in a number of wound care trials.
Amputation can also be used to save a life, but often the problem is that before its tried the infection has spread too far. Also the shock, blood loss etc, can kill a man easily, and the new wound can become infected all over again.
Blood poisoning is correctly known as septicemia, and again can be due to a number of different bacteria. The main symptom is going to be fever, often very high fevers, including shaking, argues, and of course headache and delerium etc. Survival will largely depend on the health of the patient prior to the infection, the particular bacteria involved, and things like keeping fevers down. Also whether the patient has been exposed previously to the bacteria and thus may have a natural immunity is important. Some bugs, meningococcal meningitis etc, were going to kill you regardless of any drug save massive doses of broad spectrum IV antibiotics.
Typically asparin from willow bark preparations, might have been used to fight pain and fever, some herbs as well. But prior to IV antibiotics they would have been of minimal use. Silver preparations have been tried, quacks still peddle them, but they are completely useless.
As for tetanus, the disease is caused by a toxoid released by bacteria that grow in wounds. It's a horrible way to die, and prior to the twentieth century and the development of the vaccine against the toxoid, it probably killed more soldiers than the weapons.
Poisoning as from snake bites etc, is completely different, and I believe current advice is not to suck the venom out. Apply a tournequet and get to a hospital ASAP. There's too great a chance that the suckee might get the venom into his own body and die.
If you need to check on the efficacy of any herbal preparations etc and they've been studied, chances are that there'll be a Cochrane report on it. Also you can if you've got access, check out the natural medicines database:
http://resources.library.yale.edu/online/dbsbysubjecthfxml_info.asp?searchfor=med&lookfor=YUL03570
Cheers, Greg.