Steven Aftergood brings us a tasty tidbit: According to a 1982 medical manual (PDF) for the U.S. Army Special Forces, it's sometimes okay to insert maggots into a wound to consume diseased or infected flesh if you don't have any antibiotics handy:

Despite the hazards involved, maggot therapy should be considered a viable alternative when, in the absence of antibiotics, a wound becomes severely infected, does not heal, and ordinary [removal of diseased tissue] is impossible.

As far as I can tell, "maggot therapy" is pretty uncontroversial within the medical community--they've even done experiments and everything. On the downside, it's hard to buy medicinal grade maggots these days. Also, there are risks, since maggot therapy can introduce flies into the equation, and "flies, because of their filthy habits, are likely to introduce bacteria." Also, the maggots can start chomping on live flesh, which can get ugly. So everything has to be done delicately...

Anyway, other helpful hints in the "primitive medicine" section of the manual: Intestinal worms can be combated by eating cigarettes--the nicotine "kills or stuns the worms long enough for them to be passed." Alternatively, you can drink kerosene: "Drink 2 tablespoons. Don't drink more." Fair enough.