From what I've read-
mild neurotoxic venom. Garter snakes cannot kill humans with the small amounts of venom they produce, which is comparatively mild, and they also lack an effective means of delivering it. They do have enlarged teeth in the back of their mouth, but their gums are significantly larger. Whereas most venomous snakes have anterior or forward venom glands, the Duvernoy's gland of garters are posterior (to the rear) of the snake's eyes. The mild venom is spread into wounds through a chewing action.