Agkistrodon contortrix phaeogaster was formerly a venomous pit viper subspecies[3] found in the central region of the United States.

[9] Found in the United States in eastern Kansas, extreme southeastern Nebraska and a large part of Missouri.

Immediate and severe pain, oozing of blood from the fang punctures, considerable edema, epistaxis, bleeding of the gums, marked hematuria, general petechiae, shock, renal failure, and local necrosis.

Many other toxins are present in the venom in small quantities and are not clinically significant due to their extremely low concentrations.

Patients also receive a prescription for an intensive antibiotic therapy, which much be taken until the supplies are depleted, giving the drug enough time to fully treat any opportunistic infections resulting from the bite wounds or other transmission methods which the victim's weakened immune system cannot defend against.

CroFab antivenin is effective in treating A.C. phaeogaster bites, but it may cause severe anaphylactic shock and should not be used in any individuals allergic to anything contained within the formula, unless the allergy is limited to nonlethal grievances such as rashes and itching.