Has nothing to do with chemical warfare, but here are a few suggestions from "Where There Is No Doctor", available from The Hesperian Foundation:

Penicillin, 250 mg tablets
Co-trimoxazole 400mg with trimethoprim, 80 mg
Ampicillin, 250 mg capsules
Mebendazole 100mg tablets
Lindane 20gm
Promethazine 25 mg
Antibiotic eye ointment
Penicillin, injectable, 600 000 u per ml
Ampicillin, injectable, 250 mg ampules
Streptomycin, 1gm vials
Tetracycline, 250 mg
Metronidiazole 250 mg
Ergonovine, 0.2 mg
tetanus antitoxin, 50 000 u., lyophilized
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Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, a critter that can be killed but can't be tamed. --Robert A. Heinlein